Quinoxaline-fused dibenzosuberane based helicenes and organic electroluminescent device using the same

ABSTRACT

A quinoxaline-fused dibenzosuberane based helicene is shown in formula (1), 
     
       
         
         
             
             
         
       
         
         wherein A is with a structure of formula (2), formula (3a) or formula (3b); 
       
    
     
       
         
         
             
             
         
       
         
         X is an oxygen atom, sulfur atom, amino group, or —(CH 2 ) n , wherein n is 0, 1, or 2; 
         R 1  and R 2  are independently selected from the group consisting of a hydrogen atom, a halogen atom, formula (4), formula (5) and formula (6); and 
       
    
     
       
         
         
             
             
         
       
         
         R 3  to R 15  are independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, an alkyl group, a cycloalkyl group, an alkoxy group, a thioalkyl group, a silyl group, an alkenyl group, an aryl group, a heteroaryl group, and an amino group.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending application Ser. No.15/692,820 filed on Aug. 31, 2017, which claims priority under 35 U.S.C.§ 119(a) on Patent Application No(s). 106115857 filed in Taiwan,Republic of China on May 12, 2017, and the entire contents of which areherein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of Invention

The present invention relates to an organic electroluminescent materialand an organic electroluminescent device using the same and, inparticular, to a helicene derivative and the organic electroluminescentdevice using the same.

Related Art

With the advances in electronic technology, a light weight and highefficiency flat display device has been developed. An organicelectroluminescent device becomes the mainstream of the next generationflat panel display device due to its advantages of self-luminosity, norestriction on viewing angle, power conservation, simple manufacturingprocess, low cost, high response speed, full color and so on.

In general, the organic electroluminescent device includes an anode, anorganic luminescent layer and a cathode. When applying a direct currentto the organic electroluminescent device, holes and electrons areinjected into the organic luminescent layer from the anode and thecathode, respectively. Charge carriers move and then recombine in theorganic luminescent layer because of the potential difference caused byan applied electric field. The excitons generated by the recombinationof the electrons and the electron holes may excite the luminescentmolecules in the organic luminescent layer. The excited luminescentmolecules then release the energy in the form of light.

Moreover, the selection of organic electroluminescent material is notonly based on the matching of HOMO and LUMO energy levels but alsocounts on the high decomposition temperature in order to avoid pyrolysisduring thermal vacuum deposition and also thus avoid the decrease inthermal stability.

Accordingly, it is an urgent need to provide an organicelectroluminescent material and an organic electroluminescent deviceusing the same which have high luminous efficiency, and excellentthermal stability and film forming ability.

SUMMARY OF THE INVENTION

In view of the foregoing objectives, the invention provides aquinoxaline-fused dibenzosuberane based helicene and an organicelectroluminescent device by using the same. The quinoxaline-fuseddibenzosuberane based helicene has excellent luminous efficiency,thermal stability, and film forming ability.

To achieve the above objective, a quinoxaline-fused dibenzosuberanebased helicene according to the present disclosure has a structure ofthe following General Formula (1).

In General Formula (1), A is represented by General Formula (2), GeneralFormula (3a) or General Formula (3b).

In General Formula (1), X is an oxygen atom, sulfur atom, amino group,or —(CH₂)_(n), n is 0, 1, or 2; R₁ and R₂ are both independentlyhydrogen atom, halogen atom, General Formula (4), General Formula (5) orGeneral Formula (6),

In General Formula (1), R₃ to R₁₅ are independently selected from thegroup consisting of hydrogen atom, halogen atom, cyano group, alkylgroup, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group,silyl group, alkenyl group, aryl group, and amino group.

To achieve the above objective, an organic electroluminescent device isalso disclosed. The organic electroluminescent device comprises a firstelectrode layer, a second electrode layer and an organic luminescentunit. The organic luminescent unit is deposited between the firstelectrode layer and the second electrode layer. The organic luminescentunit has at least a quinoxaline-fused dibenzosuberane based helicene asshown in General Formula (1).

In General Formula (1), A is represented by General Formula (2), GeneralFormula (3a) or General Formula (3b).

In General Formula (1), X is an oxygen atom, sulfur atom, amino group,or —(CH₂)_(n), n is 0, 1, or 2; R₁ and R₂ are both independentlyhydrogen atom, halogen atom, General Formula (4), General Formula (5) orGeneral Formula (6).

In General Formula (1), R₃ to R₁₅ are independently selected from thegroup consisting of hydrogen atom, halogen atom, cyano group, alkylgroup, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group,silyl group, alkenyl group, aryl group, and amino group.

In one embodiment, the alkyl group is selected from the group consistingof a substituted or unsubstituted straight-chain alkyl group with thecarbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain alkyl group with the carbon number of 3 to 6. Thecycloalkyl group is a substituted or unsubstituted cycloalkyl group withthe carbon number of 3 to 6. The alkoxy group is selected from the groupconsisting of a substituted or unsubstituted straight-chain alkoxy groupwith the carbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain alkoxy group with the carbon number of 3 to 6. Thehaloalkyl group is selected from the group consisting of a substitutedor unsubstituted straight-chain haloalkyl group with the carbon numberof 1 to 6, and a substituted or unsubstituted branched-chain haloalkylgroup with the carbon number of 3 to 6. The thioalkyl group is selectedfrom the group consisting of a substituted or unsubstitutedstraight-chain thioalkyl group with the carbon number of 1 to 6, and asubstituted or unsubstituted branched-chain thioalkyl group with thecarbon number of 3 to 6. The silyl group is selected from the groupconsisting of a substituted or unsubstituted straight-chain silyl groupwith the carbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain silyl group with the carbon number of 3 to 6. The alkenylgroup is selected from the group consisting of a substituted orunsubstituted straight-chain alkenyl group with the carbon number of 2to 6, and a substituted or unsubstituted branched-chain alkenyl groupwith the carbon number of 3 to 6. The aryl group is a substituted orunsubstituted aromatic hydrocarbon group with the carbon number of 6 to16, or a substituted or unsubstituted hetero aromatic ring with thecarbon number of 5 to 16. The amino group is a secondary amino group ora tertiary amino group.

In one embodiment, R₁₃ is an amino group or a substituted orunsubstituted straight-chain alkyl group with the carbon number of 1 to6.

In one embodiment, R₁₄ is a substituted or unsubstituted straight-chainalkyl group with the carbon number of 1 to 6.

In one embodiment, R₁₅ is an aryl group or a substituted orunsubstituted straight-chain alkyl group with the carbon number of 1 to6.

In one embodiment, the quinoxaline-fused dibenzosuberane based heliceneis represented by one of following chemical formula I to chemicalformula IV.

In one embodiment, the quinoxaline-fused dibenzosuberane based helicenehas glass transition temperatures ranged from 108° C. to 146° C. anddecomposition temperatures ranged from 385° C. to 547° C.

In one embodiment, the quinoxaline-fused dibenzosuberane based helicenehas oxidation potentials ranged from 0.6V to 1.0V and redox potentialsranged from −1.60V to −1.66V.

In one embodiment, the quinoxaline-fused dibenzosuberane based helicenehas highest occupied molecular orbital energy levels (E_(HOMO)) rangedfrom −5.28 eV to −5.98 eV and lowest unoccupied molecular orbital energylevels (E_(LUMO)) ranged from −3.14 eV to −3.20 eV.

In one embodiment, the organic luminescent unit comprises an organicluminescent layer.

In one embodiment, the organic luminescent unit further comprises a holetransport layer and an electron transport layer, and the organicluminescent layer is deposited between the hole transport layer and theelectron transport layer.

In one embodiment, the organic luminescent unit further comprises a holeinjection layer, a hole transport layer, an electron transport layer andan electron injection layer, and the hole transport layer, the organicluminescent layer and the electron transport layer are sequentiallydeposited between the hole injection layer and the electron injectionlayer.

In one embodiment, the organic luminescent layer comprises thequinoxaline-fused dibenzosuberane based helicene.

In one embodiment, the organic luminescent layer comprises a hostmaterial and a guest material, and the guest material comprises thequinoxaline-fused dibenzosuberane based helicene.

In one embodiment, the quinoxaline-fused dibenzosuberane based helicenewhich represented by one of following chemical formula I to chemicalformula IV is applied in an organic electroluminescent device for beingas a light emitting material, a hole-transporting material and/or anelectron-transporting material.

As mentioned above, the quinoxaline-fused dibenzosuberane based heliceneaccording to some embodiments of the present invention has excellentfluorescence quantum effect and thermal stability. Therefore, thequinoxaline-fused dibenzosuberane based helicene is suitable for anorganic electroluminescent device with excellent luminous efficiency andthermal stability.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will become more fully understood from the detaileddescription and accompanying drawings, which are given for illustrationonly, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a cross-sectional schematic diagram of an organicelectroluminescent device of the second embodiment according to theinvention;

FIG. 2 is a cross-sectional schematic diagram of an organicelectroluminescent device of the third embodiment according to theinvention; and

FIG. 3 is a cross-sectional schematic diagram of an organicelectroluminescent device of the fourth embodiment according to theinvention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments of the invention will be apparent from the followingdetailed description, which proceeds with reference to the accompanyingdrawings, wherein the same references relate to the same elements.

Quinoxaline-Fused Dibenzosuberane Based Helicene

A quinoxaline-fused dibenzosuberane based helicene according to thefirst embodiment of the present invention has a structure of thefollowing General Formula (1).

In General Formula (1), A is represented by General Formula (2), GeneralFormula (3a) or General Formula (3b).

In General Formula (1), X is an oxygen atom, sulfur atom, amino group,or —(CH₂)_(n). n is 0, 1, or 2. R₁ and R₂ are each independently ahydrogen atom, a halogen atom, or a substituent with a structurerepresented by General Formula (4), General Formula (5) or GeneralFormula (6).

In General Formula (1), R₃ to R₁₅ are independently selected from thegroup consisting of a hydrogen atom, halogen atom, cyano group, alkylgroup, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group,silyl group, alkenyl group, aryl group, and amino group.

In the present embodiment, the alkyl group is selected from the groupconsisting of a substituted or unsubstituted straight-chain alkyl groupwith the carbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain alkyl group with the carbon number of 3 to 6. Thecycloalkyl group is a substituted or unsubstituted cycloalkyl group withthe carbon number of 3 to 6. The alkoxy group is selected from the groupconsisting of a substituted or unsubstituted straight-chain alkoxy groupwith the carbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain alkoxy group with the carbon number of 3 to 6. Thehaloalkyl group is selected from the group consisting of a substitutedor unsubstituted straight-chain haloalkyl group with the carbon numberof 1 to 6, and a substituted or unsubstituted branched-chain haloalkylgroup with the carbon number of 3 to 6. The thioalkyl group is selectedfrom the group consisting of a substituted or unsubstitutedstraight-chain thioalkyl group with the carbon number of 1 to 6, and asubstituted or unsubstituted branched-chain thioalkyl group with thecarbon number of 3 to 6. The silyl group is selected from the groupconsisting of a substituted or unsubstituted straight-chain silyl groupwith the carbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain silyl group with the carbon number of 3 to 6. The alkenylgroup is selected from the group consisting of a substituted orunsubstituted straight-chain alkenyl group with the carbon number of 2to 6, and a substituted or unsubstituted branched-chain alkenyl groupwith the carbon number of 3 to 6. The aryl group is a substituted orunsubstituted aromatic hydrocarbon group with the carbon number of 6 to16, or a substituted or unsubstituted hetero aromatic ring with thecarbon number of 5 to 16. The amino group is a secondary amino group ora tertiary amino group.

When the R₁ and R₂ in the quinoxaline-fused dibenzosuberane basedhelicene according to the first embodiment of the present invention areboth represented by General formula (4), R₁₃ is an amino group or asubstituted or unsubstituted straight-chain alkyl group with the carbonnumber of 1 to 6. On the other hand, when the R₁ and R₂ in thequinoxaline-fused dibenzosuberane based helicene according to the firstembodiment of the present invention are both represented by Generalformula (5), R₁₄ is a substituted or unsubstituted straight-chain alkylgroup with the carbon number of 1 to 6. When the R₁ and R₂ in thequinoxaline-fused dibenzosuberane based helicene according to the firstembodiment of the present invention are both represented by Generalformula (6), R₁₅ is an aryl group or a substituted or unsubstitutedstraight-chain alkyl group with the carbon number of 1 to 6.

Accordingly, the quinoxaline-fused dibenzosuberane based helicenes inthe present embodiment can be a series of compounds which arerepresented by the following General Formula (1-2-1) to General Formula(1-3b-5).

General Formula (1-2-1) to General Formula (1-2-5).

General Formula (1-3a-1) to General Formula (1-3a-5).

General Formula (1-3b-1) to General Formula (1-3b-5).

The selections of the substituents of R₁ to R₁₂ in General Formula(1-2-1) to General Formula (1-3b-5) are substantially the same as thosein General Formula (1) and are therefore omitted here.

The quinoxaline-fused dibenzosuberane based helicene according to thepresent embodiment can be represented by following chemical formula I tochemical formula IV.

In the present embodiment, the quinoxaline-fused dibenzosuberane basedhelicene which is represented by General Formula (1) has a core templatewith a quinoxaline fragment as its upper panel and a helicene fragment(tetrahydro-naphthalene or tetrahydro-phenanthrene) as its lower panel.Therefore, the resulting quinoxaline-fused dibenzosuberane basedhelicene compounds are suitable for an organic luminescent material,hole transport material, and/or electron transport material with highefficiency and excellent thermal stability.

In the present embodiment, the quinoxaline-fused dibenzosuberane basedhelicene materials have glass transition temperatures ranged from 108°C. to 146° C., decomposition temperatures ranged from 385° C. to 547°C., oxidation potentials ranged from 0.6V to 1.0V and redox potentialsranged from −1.60V to −1.66V. In addition, the highest occupiedmolecular orbital energy levels (E_(HOMO)) of the quinoxaline-fuseddibenzosuberane based helicene materials are ranged from −5.28 eV to−5.98 eV and the lowest unoccupied molecular orbital energy levels(E_(LUMO)) of the quinoxaline-fused dibenzosuberane based helicenematerials are ranged from −3.14 eV to −3.20 eV.

The thermal, optical, and electrochemical properties of thequinoxaline-fused dibenzosuberane based helicene according to thepresent embodiment are further illustrated in the following experimentalexamples.

Organic Electroluminescent Device

Please refer to FIG. 1, an organic electroluminescent device 100 of thesecond embodiment according to the disclosure includes a first electrodelayer 120, a second electrode layer 140 and an organic luminescent unit160. In the embodiment, the first electrode layer 120 can be atransparent electrode material, such as indium tin oxide (ITO), and thesecond electrode layer 140 can be a metal, transparent conductivesubstance or any other suitable conductive material. On the other hand,the first electrode layer 120 can also be a metal, transparentconductive substance or any other suitable conductive material, and thesecond electrode layer 140 can also be a transparent electrode material.Overall, at least one of the first electrode layer 120 and the secondelectrode layer 140 of the embodiment is a transparent electrodematerial, so that the light emitted from the organic luminescent unit160 may pass through the transparent electrode, thereby enabling theorganic electroluminescent device 100 to emit light.

In addition, please also refer to FIG. 1, the organic luminescent unit160 can comprise a hole transport layer 162, an electron blocking layer164, an organic luminescent layer 166, a hole blocking layer 167, anelectron transport layer 168 and an electron injection layer 169. Theelectron blocking layer 164, the organic luminescent layer 166, the holeblocking layer 167 and the electron transport layer 168 are sequentiallydeposited between the hole transport layer 162 and the electroninjection layer 169.

Herein, the materials of the hole transport layer 162 can be1,1-Bis[4-[N,N′-di(p-tolyl)amino]phenyl]cyclohexane (TAPC),N,N-bis-(1-naphthyl)-N,N-diphenyl-1,1-biphenyl-4,4-diamine (NPB),N—N′-diphenyl-N—N′bis(3-methylphenyl)-[1-1′-biphenyl]-4-4′-diamine(TPD), or 4,4′,4″-tri(N-carbazolyl)triphenylamine (TCTA) and so on.Moreover, the thickness of the hole transport layer 162 of theembodiment is, for example, greater than 0 nm and no more than 40 nm.The materials of electron blocking layer 164 can beN,N′-dicarbazolyl-3,5-benzene (mCP) or other materials which have lowerelectron affinity. The materials of hole blocking layer 167 can be2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), or9,10-bis(3-(pyridin-3-yl)phenyl)anthracene (DPyPA). Moreover, thethickness of the hole blocking layer 167 of the embodiment is, forexample, greater than 0 nm and no more than 15 nm.

The materials of the electron transport layer 168 can beTris-(8-hydroxyquinoline)aluminum (Alq₃), or2,2,2-(1,3,5-benzenetriyl)-tris(1-phenyl-1-H-benzimidazole) (TBPI). Inthe embodiment, the thickness of the electron transport layer 168 is,for example, greater than 0 nm and no more than 45 nm. The electrontransport layer 168 may further increase the transport rate of theelectron from the electron injection layer 169 to the organicluminescent layer 166.

In addition, the thickness of the organic luminescent layer 166 of theembodiment is between 5 nm and 45 nm, for example, 15 nm or 40 nm. Thequinoxaline-fused dibenzosuberane based helicene which has a structureof General Formula (1) can be a suitable material used in the organicluminescent layer 166, the hole transport layer 162, and/or the electrontransport layer 168.

In General Formula (1), A is represented by General Formula (2), GeneralFormula (3a) or General Formula (3b).

In General Formula (1), X is an oxygen atom, sulfur atom, amino group,or —(CH₂)_(n). n is 0, 1, or 2. R₁ and R₂ are each independently ahydrogen atom, a halogen atom, or a substituent which can be representedby the following General Formula (4), General Formula (5) or GeneralFormula (6).

In addition, the various examples and the selection of the substituentsof R₁ to R₁₅ of General Formula (1), as well as their properties, suchas their decomposition temperatures (T_(d)), oxidation potentials, redoxpotentials, highest occupied molecular orbital energy levels (E_(HOMO)),and lowest unoccupied molecular orbital energy levels (E_(LUMO)), aresubstantially the same as those in the first embodiment and aretherefore omitted here.

In addition, FIG. 2 is a cross-sectional schematic diagram of an organicelectroluminescent device 200 of the third embodiment according to theinvention. The configuration of the organic electroluminescent device200 is substantially similar with that of the organic electroluminescentdevice 100, and same elements have substantial the same characteristicsand functions. Therefore, the similar references relate to the similarelements, and detailed explanation is omitted hereinafter.

Please refer to FIG. 2, in the embodiment, the organic luminescent unit160 can comprise a hole transport layer 162, an organic luminescentlayer 166 and an electron transport layer 168. The organic luminescentlayer 166 is deposited between the hole transport layer 162 and theelectron transport layer 168.

In addition, FIG. 3 is a cross-sectional schematic diagram of an organicelectroluminescent device 300 of the fourth embodiment according to theinvention. The configuration of the organic electroluminescent device300 is substantially similar with that of the organic electroluminescentdevice 100, and same elements have substantial the same characteristicsand functions. Therefore, the similar references relate to the similarelements, and detailed explanation is omitted hereinafter.

Please refer to FIG. 3, in the embodiment, the organic luminescent unit160 can comprise an organic luminescent layer 166.

Moreover, the configuration of the organic electroluminescent deviceaccording to the invention is not limited to what is disclosed in thesecond, third or fourth embodiment. The second, third and fourthembodiments are embodiments for illustration.

To illustrate the synthesis of the compounds according to theembodiment, there are several examples shown below.

Example 1: Synthesis of Compound 1 (1,2,3,4-tetrahydro-1-naphthalenonehydrazone)

A two-necked 100 mL flask was installed on a Dean-Stark trap and thendried under vacuum. Ethanol (30 mL) was added to the 100 ml flask,followed by adding α-tetralone (400 μL, 3 mmol) and hydrazinemonohydrate (2.62 mL, 54 mmol) into the flask by a syringe. The flaskcontaining the reaction mixture was then put in an oil bath at 120° C.for being refluxed for 2 hours, and then the flask was removed from theheating system and cooled down to room temperature. The ethanol wasremoved by a vacuum system so as to obtain the product 1 (yield: 100%).Because the product 1 tended to decompose easily, it was used for thefollowing reactions without purification. The above reaction isrepresented by the chemical equation (1-1).

Spectral data as follow: M.W.: 106.10; ¹H NMR (400 MHz, CDCl₃) δ 8.32(d, J=7.6, 1H), 7.21-7.16 (m, 2H), 7.11 (t, J=2.4, 1H), 5.32 (s, 1H),2.73 (t, J=6.4, 2H), 2.47 (t, J=6.8, 2H), 1.92 (dd, J=6.4, 2.4, 2H).

Example 2: Synthesis of Compound 2 (dibenzo[a,d]cycloheptene-5-thione)

P₄S₁₀ (2.68 g, 6.03 mmol) and anhydrous CH₃CN (10 mL) were added to atwo-necked, round-bottomed 100 mL flask. Dibenzosuberenone (1.054 g,5.11 mmol) dissolved by anhydrous CH₃CN (15 mL) was added into anothertwo-necked, round-bottomed flask, and was injected to the first (100 ml)flask by a double-tipped needle. The mixture was then reacted for 2 daysat room temperature, and the reaction was quenched by the followingsteps. The reaction mixture was first filtered by Al₂O₃ to removed P₄S₁₀and P₄O₁₀. The green filtrate (liquid) was then condensed with a rotaryevaporator to obtain a crude product. The crude product was thenpurified by column chromatography by using a mixture of EtOAc/hexanes(1/30) as an eluent, and followed by recrystallization with n-hexane, soas to obtain the green compound 2 (569 mg, yield: 50%). The abovereaction is represented by the chemical equation (1-2).

Spectral data as follow: M.W.: 222.30; ¹H NMR (400 MHz, CDCl₃) δ 8.03(dd, J=7.8, 0.9, 2H), 7.50 (td, J=7.5, 1.2, 2H), 7.42-7.35 (m, 4H), 6.99(s, 2H); NMR (100 MHz, CDCl₃) δ 149.52, 136.48, 130.97, 129.54, 128.95,126.28, 33.73; TLC R_(f)=0.43 (EtOAc/hexanes, 1/30); Elemental Analysis.Calcd for C₁₅H₁₂S: C, 80.32; H, 5.39; Found: C, 80.33; H, 5.42.

Example 3a: Synthesis of Compound 3a(1′H-thiochromane-1′-2″-thiirane-3″-10,11-dihydro-5H-dibenzo[a,d]cycloheptene)

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 50 ml flask which was then dried by vacuum. The compound 1(480.3 mg, 3 mmol) dissolved in anhydrous dichloromethane (10 mL) wastransferred into the flask installed at the bottom end of the Schlenktube by a double-tipped needle. At −10° C., dried silver(I) oxide (1.04g, 4.5 mmol) and magnesium sulfate (1.95 g) were well mixed and thenpoured into the flask at bottom end of the Schlenk tube. Saturatedpotassium hydroxide solution (in methanol, 2.35 mL) was dropwiselyinjected into the flask at the bottom end of the Schlenk tube. Afterreacting for 40 minutes at −10° C., the Schlenk tube was inverted tofilter out the solid impurities (i.e., silver(I) oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at0° C. The compound 2 (thioketone, 333.8 mg, 1.57 mmol) dissolved inanhydrous dichloromethane (15.7 mL, concentration: 0.1M) was then slowlyinjected into the flask containing the filtrate with an air-tightsyringe until no bubbles were produced in the solution and the color ofthe solution became light green (the color of compound 2). Afterreacting for 9 hours at 0° C., the reaction mixture was added withsaturated, aqueous sodium bicarbonate solution (10 mL) to quench thereaction. The organic layer of the reaction mixture was then extractedwith dichloromethane (150 mL). The collected organic layer was dried byadding anhydrous magnesium sulfate, followed by filtration andcondensation to obtain a crude product. The crude product was thenpurified by column chromatography by using a mixture of ether/hexane(1/100) as an eluent, and was then recrystallized with a mixture ofhexanes/dichloromethane, so as to obtain the compound 3a (243 mg, yield:69%). The above reaction is represented by the chemical equation (1-3a).

Spectral data as follow: M.W.: 352.49; mp 112-116° C.; ¹H NMR: (400 MHz,CDCl₃) δ 7.85 (d, J=7.8, 1H), 7.69 (d, J=7.5, 1H), 7.33-7.19 (m, 4H),7.08 (t, J=7.3, 1H), 6.92-6.89 (m, 2H), 6.83-6.78 (m, 2H), 6.48 (d,J=11.7, 1H), 6.40 (dt, J=8, 1.9, 1H), 6.35 (d, J=7.8, 1H), 2.70 (t,J=5.6, 2H), 1.93 (dt, J=11.5, 3.4, 1H), 1.87-1.80 (m, 1H), 1.56-1.48 (m,1H), 1.36-1.30 (m, 1H); ¹³C NMR: (100 MHz, CDCl₃) δ 139.94, 139.85,137.73, 135.61, 135.16, 134.81, 132.23, 131.50, 131.34, 130.08, 129.47,129.13, 129.84, 128.70, 128.36, 127.57, 127.49, 127.18, 126.91, 124.39,68.68, 56.91, 34.99, 29.22, 21.55; MS: (20 eV) 352 (M⁺, 60), 351(31),319 (12), 189 (100); Analysis: (C₂₅H₂₀S (352.49)) Calcd: C, 85.18; H,5.72; S, 9.10; Found: C, 85.23; H, 5.79; TLC: R_(f) 0.3 (hexane/ether,100/1).

Example 3b: Synthesis of Compound 3b(2″,3″-dihydrodispiro[dibenzo[a,d][7]annulene-5,2′-thiirane-3′,1″-indene])

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 100 ml flask which was then dried by vacuum. The compound 1b(488.5 mg, 3 mmol) dissolved in anhydrous dichloromethane (30 mL) wastransferred into the flask installed at bottom end of the Schlenk tubeby a double-tipped needle. At −10° C., dried silver(I) oxide (1.04 g,4.5 mmol) and magnesium sulfate (1.96 g) were well mixed and then pouredinto the flask at bottom end of the Schlenk tube, followed by beingdropwisely added with saturated potassium hydroxide solution (inmethanol, 0.87 mL). After reacting for 40 minutes at −10° C., theSchlenk tube was inverted to filter out the solid impurities (i.e.,silver(I) oxide and magnesium sulfate) and thus to collect the dark-redfiltrate in the other two-necked flask. Then the flask containing thefiltrate was placed at 0° C. The compound 2 (thioketone, 401.9 mg, 1.8mmol) dissolved in anhydrous dichloromethane (18 mL) was then slowlyinjected into the flask containing the filtrate with an air-tightsyringe until no bubbles were produced in the solution and the color ofthe solution became light green (the color of compound 2). Afterreacting for 10 hours at 0° C., the reaction mixture was added withsaturated, aqueous sodium bicarbonate solution (10 mL) to quench thereaction. The organic layer of the reaction mixture was then extractedwith dichloromethane (150 mL) for three times. Then, the collectedorganic layer was dried by adding anhydrous magnesium sulfate, followedby filtration and condensation to obtain a condensed solution. Thecondensed solution was then purified by column chromatography by usingn-hexane as an eluent to obtain a crude product. The crude product wasthen recrystallized with n-hexane, so as to obtain the compound 3b(222.9 mg, yield: 37%). The above reaction is represented by thechemical equation (1-3b).

Spectral data as follow: m.p.: 138-141° C.; ¹H NMR: (400 MHz, CDCl₃)7.85 (d, J=8.0, 1H), 7.70 (d, J=8.0, 1H), 7.73 (dt, J=8.0, 4.0, 2H),7.28-7.21 (m, 2H), 7.19 (t, J=8.0, 1H), 7.05-6.98 (m, 3H), 6.89 (d,J=12.0, 1H), 6.63 (t, J=8.0, 1H), 6.42 (d, J=12, 1H), 5.76 (d, J=8.0,1H), 2.94-2.81 (m, 2H), 2.24-2.16 (m, 1H), 1.70-1.64 (m, 1H); ¹³C NMR:(100 MHz, CDCl₃) 145.18, 145.18, 142.96, 140.72, 138.92, 135.63, 135.18,132.1, 131.17, 130.58, 129.75, 128.72, 127.96, 127.63, 127.36, 126.05,124.85, 124.1, 64.92, 63.59, 34.55, 29.57; MS: (20 eV) 338 (M⁺, 100),337 (20), 189 (94), 115 (10), 91 (28); TLC: R_(f)0.37 (hexane).

Example 3c: Synthesis of Compound 3c(6,7,8,9-tetrahydrodispiro[benzo[7]annulene-5,2′-thiirane-3′,5″-dibenzo[a,d][7]annulene])

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 100 ml flask which was then dried by vacuum. The compound 1c(522.7 mg, 3 mmol) dissolved in anhydrous dichloromethane (25 mL) wasthen transferred into the flask installed at bottom end of the Schlenktube by a double-tipped needle. At −10° C., dried silver(I) oxide (1.04g, 4.5 mmol) and magnesium sulfate (1.96 g) were well mixed and thenpoured into the flask at bottom end of the Schlenk tube, followed bydropwisely addition of saturated potassium hydroxide solution (inmethanol, 2.4 mL) into the flask at bottom end of the Schlenk tube.After reacting for 40 minutes at −10° C., the Schlenk tube was invertedto filter out the solid impurities (i.e., silver oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at0° C. The compound 2 (thioketone, 552 mg, 2.48 mmol) dissolved inanhydrous dichloromethane (24.5 mL) was slowly injected into the flaskcontaining the filtrate with an air-tight syringe until no bubbles wereproduced in the solution and the color of the solution became lightgreen (the color of compound 2). After reacting for 4 hours at 0° C.,the reaction mixture was added with saturated, aqueous sodiumbicarbonate solution (5 mL) to quench the reaction. The organic layer ofthe reaction mixture was then extracted with ether (200 mL) for threetimes. Then, the collected organic layer was dried by adding anhydrousmagnesium sulfate, followed by filtration and condensation to obtain acondensed solution. The condensed solution was then purified by columnchromatography using a mixture of ether/n-hexane (1/100) as an eluent,so as to obtain a crude product. The crude product was recrystallizedwith n-hexane to obtain the compound 3c (654 mg, yield: 73%). The abovereaction is represented by the chemical equation (1-3c).

Spectral data as follow: m.p.: 137-140° C.; ¹H NMR: (200 MHz, CDCl₃)7.79-7.72 (m, 2H), 7.42-6.84 (m, 10H), 6.78 (d, J=12.0, 1H), 6.64-6.55(m, 1H), 3.3-3.21 (m, 1H), 2.63 (dt, 1H, J=14.0, 4.0), 2.05-1.96 (m,1H), 1.66-1.45 (m, 5H); ¹³C NMR: (50 MHz, CDCl₃) 141.40, 139.32, 137.65,137.12, 134.79, 134.54, 132.59, 132.59, 131.25, 130.98, 130.61, 129.92,129.82, 128.46, 128.02, 127.56, 126.94, 126.94, 126.47, 124.7, 69.49,65.33, 37.99, 33.50, 26.55, 23.16; MS: (20 eV) 366 (M⁺, 100), 333 (11),191 (35); TLC: R_(f) 0.47 (hexane/ether, 100/1).

Example 3d: Synthesis of Compound 3d(dispiro[chromane-4,2′-thiirane-3′,5″-dibenzo[a,d][7]annulene])

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 100 ml flask which was then dried by vacuum. The compound 1d(454.1 mg, 3 mmol) dissolved in anhydrous dichloromethane (25 mL) wasthen transferred into the flask installed at bottom end of the Schlenktube by a double-tipped needle. At −10° C., dried silver(I) oxide (1.04g, 4.5 mmol) and magnesium sulfate (1.96 g) were well mixed and thenpoured into the flask at bottom end of the Schlenk tube, followed bydropwisely addition of saturated potassium hydroxide solution (inmethanol, 2.4 mL) into the flask at bottom end of the Schlenk tube.After reacting for 40 minutes at −10° C., the Schlenk tube was invertedto filter out the solid impurities (i.e., silver oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at0° C. The compound 2 (thioketone, 552 mg, 2.48 mmol) dissolved inanhydrous dichloromethane (24.5 mL) was slowly injected into the flaskcontaining the filtrate with an air-tight syringe until no bubbles wereproduced in the solution and the color of the solution became lightgreen (the color of compound 2). After reacting for 4 hours at 0° C.,the reaction mixture was added with saturated, aqueous sodiumbicarbonate solution (5 mL) to quench the reaction. The organic layer ofthe reaction mixture was then extracted with ether (200 mL) for threetimes. Then, the collected organic layer was dried by adding anhydrousmagnesium sulfate, followed by filtration and condensation to obtain acondensed solution. The condensed solution was then purified by columnchromatography by using a mixture of ether/n-hexane (1/100) as aneluent, so as to obtain a crude product. The crude product wasrecrystallized with n-hexane to obtain the compound 3d (106 mg, yield:30%). The above reaction is represented by the chemical equation (1-3d).

Spectral data as follow: m.p.: 208-211° C.; ¹H NMR: (200 MHz, CDCl₃)7.92 (d, J=8, 1H), 7.73 (d, J=8.0, 1H), 7.44-7.28 (m, 5H), 7.26-7.14 (m,3H), 7.07-6.72 (m, 2H), 6.66-6.61 (m, 2H), 6.27-6.24 (m, 2H), 4.25 (td,J=11.0, 3.0, 1H), 4.10-4.00 (m, 1H), 2.27 (td, J=12.0, 4.0, 1H), 1.42(dt, J=12.0, 3.0, 1H); ¹³C NMR: (50 MHz, CDCl₃) 156.41, 136.44, 134.92,134.1, 131.48, 131.43, 130.81, 130.81, 129.7, 129.23, 128.78, 128.41,128.31, 127.93, 127.32, 127.23, 126.99, 120.65, 118.7, 116.19, 67.78,65.31, 52.43, 33.09; MS: (20 eV) 354 (M⁺, 100), 326 (83), 321 (72), 311(44), 293 (25), 247 (88), 221 (44), 189 (100), 178 (21), 131 (48); TLC:R_(f) 0.48 (hexane/ether, 1/20).

Example 3e: Synthesis of Compound 3e(dispiro[dibenzo[a,d][7]annulene-5,2′-thiirane-3′,4″-thiochromane])

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 100 ml flask which was then dried by vacuum. The compound 1e(5344.1 mg, 3 mmol) dissolved in anhydrous dichloromethane (30 mL) wasthen transferred into the flask installed at bottom end of the Schlenktube by a double-tipped needle. At −10° C., dried silver(I) oxide (1.04g, 4.5 mmol) and magnesium sulfate (1.96 g) were well mixed and thenpoured into the flask at bottom end of the Schlenk tube, followed bydropwisely addition of saturated potassium hydroxide solution (inmethanol, 2.4 mL) into the flask at bottom end of the Schlenk tube.After reacting for 40 minutes at −10° C., the Schlenk tube was invertedto filter out the solid impurities (i.e., silver oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at0° C. The compound 2 (thioketone, 333.4 mg, 1.5 mmol) dissolved inanhydrous dichloromethane (15 mL) was slowly injected into the flaskcontaining the filtrate with an air-tight syringe until no bubbles wereproduced in the solution and the color of the solution became lightgreen (the color of compound 2). After reacting for 4 hours at 0° C.,the reaction mixture was added with saturated, aqueous sodiumbicarbonate solution (10 mL) to quench the reaction. The organic layerof the reaction mixture was then extracted with ether (150 mL) for threetimes. Then, the collected organic layer was dried by adding anhydrousmagnesium sulfate, followed by filtration and condensation to obtain acondensed solution. The condensed solution was then purified by columnchromatography by using a mixture of ether/n-hexane (1/100) as aneluent, so as to obtain a crude product. The crude product wasrecrystallized with n-hexane to obtain the compound 3e (444 mg, yield:80%). The above reaction is represented by the chemical equation (1-3e).

Spectral data as follow: m.p.: 191-192° C.; ¹H NMR: (400 MHz, CDCl₃)7.84 (d, J=8, 1H), 7.75 (d, J=8.0, 1H), 7.39-7.27 (m, 4H), 7.10 (td,J=8.0, 2.0, 1H), 7.02 (d, J=12.0, 1H), 6.94 (d, J=8.0, 1H), 6.89 (dd,J=8.0, 2.0, 1H), 6.79 (td, J=8.0, 4.0, 1H), 6.71-6.68 (m, 2H), 6.36 (td,J=8.0, 2.0, 1H), 3.14 (td, J=12.0, 4.0, 1H), 2.54 (dt, J=12.0, 4.0, 1H),2.46 (td, J=16.0, 4.0, 1H), 1.64 (dt, J=16.0, 4.0, 1H); ¹³C NMR: (100MHz, CDCl₃) 138.01, 138.01, 136.99, 135.76, 135.56, 135.00, 131.71,131.6, 131.07, 130.81, 130.41, 129.21, 128.57, 128.39, 127.91, 127.62,127.50, 127.36, 126.05, 122.57, 69.31, 55.93, 32.79, 24.64; MS: (20 eV)370 (M⁺, 100), 342 (70), 190 (22); TLC: R_(f)0.24 (hexane/ether, 100/1).

Example 4a: Synthesis of Compound 4a(5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene)

A stir bar was placed in a 10 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 3a (244.8 mg, 0.72 mmol) dissolved in anhydrous dimethylbenzene(2 mL) was added into the 10 ml flask, followed by adding dried copperpowder (457.5 mg, 7.2 mmol). The 10 ml flask containing the reactionmixture was then put in an oil bath at 150° C. for reflux. The reactionmixture was refluxed for 2 hours, and then the red-brown copper powderwas found to become black copper sulfide. After the reaction wascompleted, a crude product was collected with a filtering funnel whichwas fitted inside with a filter paper. The flask was washed bydichloromethane to collect the residual crude product in the flask.After filtration and condensation with a rotary evaporator, a whitesolid was obtained. The obtained solid was then recrystallized with amixture of n-hexane/dichloromethane to obtain the compound 4a (207 mg,yield: 90%). The above reaction is represented by the chemical equation(1-4a).

Spectral data as follow: M.W.: 320.42; m.p.: 174-176° C.; ¹H NMR (400MHz, CDCl₃) δ 7.38-7.35 (m, 4H), 7.28-7.27 (m, 1H), 7.20 (t, J=7.4, 1H),7.12-7.11 (m, 1H), 7.05-7.04 (m, 1H), 6.97 (dd, J=7.6, 2.5, 4H), 6.66(t, J=7.5, 1H), 6.27 (d, J=7.9, 1H), 2.96-2.81 (m, 3H), 2.05-2.01 (m,2H), 1.90-1.84 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 139.23, 139.20,135.28, 135.20, 135.05, 131.36, 131.19, 129.29, 128.60, 128.58, 128.18,128.14, 127.99, 127.58, 126.50, 126.36, 126.28, 124.22, 29.57, 28.16,23.99; Elemental Analysis. Calcd for C₂₅H₂₂: C, 93.12; H, 6.88; Found:C, 92.88; H, 6.84; TLC: R_(f) 0.30 (hexane/ether, 100/1); UV λ_(max):277 nm (ε 10060, in hexane).

Example 4b: Synthesis of Compound 4b(5-(2,3-dihydro-1H-inden-1-ylidene)-5H-dibenzo[a,d][7]annulene)

A stir bar was placed in a 50 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 3b (55.5 mg, 0.13 mmol) dissolved in anhydrous dimethylbenzene(10 mL) was added into the 50 ml flask, followed by adding dried copperpowder (88.2 mg, 7.2 mmol). The 50 ml flask containing the reactionmixture was then put in an oil bath at 180° C. for reflux. The reactionmixture was refluxed for 2 hours, and then the red-brown copper powderwas found to become black copper sulfide. After the reaction wascompleted, a crude product was collected with a filtering funnel whichwas fitted inside with a filter paper. The flask was washed by ether tocollect the residual crude product in the flask. After filtration andcondensation with a rotary evaporator, a white solid was obtained. Theobtained solid was then purified by column chromatography by usingn-hexane as an eluent, and followed by being recrystallized withn-hexane to obtain the compound 4b (36.2 mg, yield: 91%). The abovereaction is represented by the chemical equation (1-4b).

Spectral data as follow: M.W.: 306.41; m.p.: 162-163° C.; ¹H NMR (400MHz, CDCl₃) δ 7.61-7.00 (m, 8H), 6.94 (s, 2H), 6.88-6.80 (m, 2H), 6.43(d, J=8.0, 1H), 3.16-2.75 (m, 3H), 2.38-2.21 (m, 1H); ¹³C NMR (100 MHz,CDCl₃) δ 148.23, 148.22, 140.90, 140.45, 140.17, 138.90, 1334.42,134.12, 131.08, 131.04, 128.70, 128.63, 128.55, 128.35, 128.1, 127.76,127.55, 127.00, 126.30, 125.93, 125.14, 30.34, 29.60; MS (20 eV) 306(M⁺, 100); Elemental Analysis. Calcd for C₂₄H₁₈: C, 94.07; H, 5.93;Found: C, 94.02; H, 5.96; TLC: R_(f) 0.34 (hexane/ether, 100/1); UVλ_(max): 278 nm (ε 21200, in hexane).

Example 4c: Synthesis of Compound 4c(5-(6,7,8,9-tetrahydro-5H-benzo[7]annulen-5-ylidene)-5H-dibenzo[a,d][7]annulene)

A stir bar was placed in a 50 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 3c (100 mg, 0.27 mmol) dissolved in anhydrous dimethylbenzene(10 mL) was added into the 50 ml flask, followed by adding dried copperpowder (176.8 mg, 2.72 mmol). The 50 ml flask containing the reactionmixture was then put in an oil bath at 180° C. for reflux. The reactionmixture was refluxed for 2 hours, and then the red-brown copper powderwas found to become black copper sulfide. After the reaction wascompleted, a crude product was collected with a filtering funnel whichwas fitted inside with a filter paper. The flask was washed by ether tocollect the residual crude product in the flask. After filtration andcondensation with a rotary evaporator, a white solid of the compound 4c(84.4 mg, yield: 93%) was obtained. The above reaction is represented bythe chemical equation (1-4c).

Spectral data as follow: M.W.: 334.45; m.p.: 152-153° C.; ¹H NMR (200MHz, CDCl₃) δ 7.57-7.52 (m, 1H), 7.42-7.21 (m, 6H), 7.07-6.88 (m, 8H),6.71 (t, J=7.8, 2H), 6.44-6.26 (bd, J=8.0, 1H), 3.09 (t, J=12.0, 1H),2.82 (t, J=12.0, 1H), 5.54-2.40 (bd, 1H), 2.04-1.87 (m, 4H), 1.60-1.40(m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 142.99, 142.98, 142.92, 141.58,138.90, 137.52, 134.70, 134.69, 131.19, 131.13, 129.86, 128.61, 128.29,128.28, 128.01, 127.79, 127.78, 127.55, 126.58, 126.2, 125.96, 125.25,36.64, 32.89, 32.37, 28.11; MS (20 eV) 334 (M⁺, 100), 305 (11), 193(12), 191 (80), 177 (11); Elemental Analysis. Calcd for C₂₆H₂₂: C,93.37; H, 6.63; Found: C, 93.44; H, 6.82; TLC: R_(f)0.47 (hexane/ether,100/1); UV λ_(max): 251 nm (ε 12300, in hexane).

Example 4d: Synthesis of Compound 4d(4-(5H-dibenzo[a,d][7]annulen-5-ylidene)chromane)

A stir bar was placed in a 50 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 3d (57.3 mg, 0.16 mmol) dissolved in anhydrous dimethylbenzene(10 mL) was added into the 50 ml flask, followed by adding dried copperpowder (102.4 mg, 1.6 mmol). The 50 ml flask containing the reactionmixture was then put in an oil bath at 180° C. for reflux. The reactionmixture was refluxed for 2 hours, and then the red-brown copper powderwas found to become black copper sulfide. After the reaction wascompleted, a crude product was collected with a filtering funnel whichwas fitted inside with a filter paper. The flask was washed by ether tocollect the residual crude product in the flask. After filtration andcondensation with a rotary evaporator, a white solid was obtained. Theobtained solid was then purified by column chromatography by using amixture of ether/n-hexane (1/100) as an eluent, and followed by beingrecrystallized with n-hexane to obtain the compound 4d (47.8 mg, yield:93%). The above reaction is represented by the chemical equation (1-4d).

Spectral data as follow: M.W.: 322.40; m.p.: 226-227° C.; ¹H NMR (400MHz, CDCl₃) δ 7.35-7.13 (m, 8H), 7.00-6.86 (m, 3H), 6.69 (m, 1H), 6.31(t, J=8.0, 1H), 6.10 (d, J=8.0, 1H), 4.49-4.46 (m, 1H), 4.34 (t, J=12.0,1H), 2.83 (d, J=3.0, 1H), 2.18 (dt, J=12.0, 3.0, 1H); ¹³C NMR (100 MHz,CDCl₃) δ 156.15, 140.20, 139.06, 135.90, 135.59, 134.50, 134.49, 131.84,130.00, 129.93, 129.61, 129.35, 129.25, 129.02, 128.92, 128.70, 127.72,127.42, 127.15, 122.85, 119.42, 117.07, 67.71, 26.77; MS (20 eV) 322(M⁺, 100); Elemental Analysis. Calcd for C₂₄H₁₈O: C, 89.40; H, 5.63;Found: C, 89.45; H, 5.55; TLC: R_(f) 0.37 (hexane/ether, 20/1); UVλ_(max): 272 nm (ε 7553, in hexane).

Example 4e: Synthesis of Compound 4e(4-(5H-dibenzo[a,d][7]annulen-5-ylidene)thiochromane)

A stir bar was placed in a 50 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 3e (60.7 mg, 0.164 mmol) dissolved in anhydrous dimethylbenzene(10 mL) was added into the 50 ml flask, followed by adding dried copperpowder (105.3 mg, 1.64 mmol). The 50 ml flask containing the reactionmixture was then put in an oil bath at 180° C. for reflux. The reactionmixture was refluxed for 2 hours, and then the red-brown copper powderwas found to become black copper sulfide. After the reaction wascompleted, a crude product was collected with a filtering funnel whichwas fitted inside with a filter paper. The flask was washed by ether tocollect the residual crude product in the flask. After filtration andcondensation with a rotary evaporator, a white solid was obtained. Theobtained solid was then purified by column chromatography by using amixture of ether/n-hexane (1/100) as an eluent, and followed by beingrecrystallized with n-hexane to obtain the compound 4e (54.5 mg, yield:99%). The above reaction is represented by the chemical equation (1-4e).

Spectral data as follow: M.W.: 338.47; m.p.: 242-243° C.; ¹H NMR (400MHz, CDCl₃) δ 7.43-6.89 (m, 12H), 6.55 (td, J=7.0, 1.0, 1H), 6.24 (dd,J=7.0, 1.4, 1H), 3.48-3.20 (m, 2H), 3.02 (dt, J=12.0, 4.0, 1H), 2.10(td, J=12.0, 5.0, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 140.47, 140.46,138.90, 137.36, 136.52, 135.79, 135.70, 134.55, 131.90, 131.88, 130.79,129.64, 129.21, 128.98, 128.70, 128.66, 127.71, 127.38, 127.32, 127.24,126.87, 123.49, 28.49, 26.83; MS (20 eV) 339 (24), 338 (M⁺, 100), 323(24), 191 (17); Elemental Analysis. Calcd for C₂₄H₁₈S: C, 85.17; H,5.36; Found: C, 84.86; H, 5.39; TLC: R_(f)0.34 (hexane/ether, 100/1); UVλ_(max): 279 nm (ε 26800, in hexane).

Example 5: Synthesis of Compound 5(5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene-10,11-dione)

A stir bar was placed in a two-necked, round-bottomed flask, and theflask was then installed to a reflux condenser system. The compound 4a(320.43 mg, 1 mmol) and benzeneseleninic anhydride (BSA, 720.26 mg, 2mmol) were added into the flask and dissolved in chlorobenzene (10 mL),followed by refluxing for 5 hours until the color of the solution turnedto orange-red. The reaction mixture was filtered by a filtering funnel,which was fitted inside with silica gel (3 cm height) in advance. Thereaction mixture was filtered with n-hexane first to remove diphenyldiselenide, and all the crude products were then filtered by washingwith dichloromethane, followed by being purified by columnchromatography by using a mixture of EtOAc/hexane (1/30) as an eluent toobtain the compound 5 (158 mg, yield: 45%). The above reaction isrepresented by the chemical equation (1-5).

Spectral data as follow: M.W.: 350.41; ¹H NMR (400 MHz, CDCl₃) δ 7.89(d, J=5.3, 1H), 7.82 (d, J=7.6, 1H), 7.56 (t, J=7.5, 1H), 7.48 (t,J=7.6, 2H), 7.33-7.30 (m, 2H), 7.08-7.01 (m, 3H), 6.69 (t, J=7.2, 1H),6.45 (d, J=7.8, 1H), 2.97-2.91 (m, 2H), 2.74-2.70 (m, 1H), 2.06-2.00 (m,3H); ¹³C NMR (100 MHz, CDCl₃) δ 189.19, 188.63, 143.13, 142.39, 142.06,139.46, 135.58, 135.47, 133.74, 132.83, 131.10, 130.73, 129.11, 129.04,128.60, 128.00, 127.93, 127.83, 127.70, 124.70, 29.44, 29.20, 23.68; TLCR_(f)=0.20 (EtOAc/hexanes, 1/30).

Example 6: Synthesis of Compound 6(1,4-dibromo-quinoxaline-5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene)

A two-necked, round-bottomed flask was installed to a reflux condensersystem. The compound 5 (350.41 mg, 1 mmol) and3,6-dibromobenzene-1,2-diamine (397 mg, 1.5 mmol) were added into theflask and dissolved in chloroform (10 mL), followed by adding p-TSA(p-toluene sulfonic acid, 8.61 mg, 5 mol %) into the flask. After thereaction mixture was refluxed for 8 hours, the mixture was extracted bydichloromethane and H₂O (30 mL/30 mL) and the organic layer was thencollected. The collected organic layer was dried by adding magnesiumsulfate, followed by being purified by column chromatography by using amixture of dichloromethane/n-hexane (1/2) as an eluent to obtain thecompound 6 (464 mg, yield: 80%). The above reaction is represented bythe chemical equation (1-6).

Spectral data as follow: M.W.: 580.31; ¹H NMR (400 MHz, CDCl₃) δ 8.27(d, J=7.7, 1H), 8.19 (d, J=7.5, 1H), 7.96 (s, 2H), 7.54-7.41 (m, 4H),7.30 (t, J=7.4, 1H), 7.08-7.00 (m, 3H), 6.72 (t, J=7.5, 1H), 6.51 (d,J=7.8, 1H), 2.96-2.86 (m, 3H), 2.07-1.90 (m, 3H); ¹³C NMR (100 MHz,CDCl₃) δ 135.24, 133.18, 132.06, 131.34, 130.21, 129.40, 128.28, 127.79,127.38, 127.11, 126.88, 125.79, 125.01, 124.63, 29.25, 27.77, 22.45; TLCR_(f)=0.50 (CH₂Cl₂/hexanes, 1/2).

Example 7a: Synthesis of Compound 7a(1,4-di-(phenyl-methoxyl)-quinoxaline-5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene)

A two-necked, round-bottomed flask was installed to a reflux condensersystem. The compound 6 (290 mg, 0.5 mmol), 4-methoxy-phenyl bonoic acid(227.94 mg, 1.5 mmol) and Na₂CO₃ (126 mg, 1.5 mmol) were added into theflask, and then the mixture was dissolved in a co-solvent systemcontaining ethylene glycol dimethyl ether (EGDME) and H₂O (5 mL,EGDME:H₂O=4:1), followed by adding Pd(PPh₃)₄ (17 mg, 3 mol %). After thereaction mixture was refluxed for 8 hours, the mixture was extracted bydichloromethane/H₂O (30 mL/30 mL) and the organic layer was collected.The collected organic layer was dried by adding magnesium sulfate,followed by being purified by column chromatography by using a mixtureof dichloromethane/n-hexane (1/1) as an eluent to obtain the compound 7a(229 mg, yield: 73%). The above reaction is represented by the chemicalequation (1-7a).

Spectral data as follow: M.W.: 636.78; m.p.: 289° C.; T_(g)=127° C.;T_(d)=398° C.; ¹H NMR (400 MHz, CDCl₃) δ 8.06 (t, J=8.0, 2H), 7.88-7.85(m, 6H), 7.44 (t, J=5.1, 1H), 7.39 (t, J=6.8, 2H), 7.30 (t, J=6.5, 1H),7.21 (t, J=6.3, 1H), 7.11-7.09 (m, 4H), 7.08-7.02 (m, 3H), 6.65 (d,J=7.4, 1H), 6.49 (d, J=7.8, 1H), 3.94 (s, 3H), 3.91 (s, 3H), 2.93-2.83(m, 3H), 2.04-1.96 (m, 2H), 1.88-1.84 (m, 1H); ¹³C NMR (100 MHz, CDCl₃)δ 159.19, 159.14, 150.85, 150.72, 144.77, 139.07, 136.56, 132.08,132.03, 131.21, 131.14, 131.01, 129.70, 129.58, 129.53, 129.40, 129.17,128.30, 127.42, 127.09, 126.96, 126.88, 124.48, 113.54, 113.40, 55.34,29.59, 28.75, 23.95; TLC R_(f)=0.60 (CH₂Cl₂/hexanes, 1/1); ElementalAnalysis. Calcd for C₄₅H₃₄N₂O₂: C, 85.15; H, 5.40; N, 4.41; O, 5.04.found: C, 85.17; H, 5.34; N, 4.10.

Example 7b: Synthesis of Compound 7b(1,4-di-(n-phenyl,n-methyl-amine)-quinoxaline-5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene)

A stir bar was placed in a 50 mL, two-necked flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 6 (580 mg, 1.0 mmol), methyl-phenyl-amine (225 mg, 2.1 mmol),Pd(dba)₂ (20 mg, 0.04 mmol) and sodium tert-butoxide (288 mg, 3.0 mmol)were added into the flask, and then the mixture was dissolved in toluene(20 mL, dehydrated by sodium in advance), followed by injecting (t-Bu)₃P(8-12 mg, 0.04-0.06 mmol). After the reaction mixture was refluxed for36 hours, deionized H₂O (30 mL) was added to quench the reaction. Themixture was then extracted by a mixture of dichloromethane/H₂O (30 mL/30mL) and the organic layer was then collected. The collected organiclayer was dried by adding magnesium sulfate, followed by being purifiedby column chromatography by using a mixture of dichloromethane/n-hexane(1/1) as an eluent to obtain the compound 7b (yield: 70%). The abovereaction is represented by the chemical equation (1-7b).

Spectral data as follow: M.W.: 632.79; m.p.: 292° C.; T_(g)=108° C.;T_(d)=385° C.; ¹H NMR (400 MHz, CDCl₃) δ 7.61 (t, J=7.3, 2H), 7.59 (m,1H), 7.36 (t, J=7.0, 1H), 7.32-7.31 (m, 1H), 7.24-7.14 (m, 7H),7.01-6.84 (m, 10H), 6.64 (t, J=7.0, 1H), 6.35 (d, J=7.9, 1H), 3.60 (s,6H), 2.91-2.79 (m, 3H), 2.04-1.95 (m, 3H); ¹³C NMR (100 MHz, CDCl₃) δ151.02, 144.51, 142.97, 136.67, 131.77, 131.29, 129.74, 129.42, 129.16,128.89, 128.81, 128.28, 127.37, 126.91, 126.83, 126.79, 126.03, 124.52,118.90, 118.57, 116.95, 116.35, 112.43, 41.55, 41.41, 29.61, 28.76,23.97; TLC R_(f)=0.60 (CH₂Cl₂/hexanes, 1/1); Elemental Analysis. Calcdfor C₄₅H₃₆N₄: C, 85.41; H, 5.73; N, 8.85. found: C, 84.96; H, 5.57; N,8.56.

Example 7c: Synthesis of Compound 7c(1,4-di-(phenyl-N,N-diphenyl-amine)-quinoxaline-5-(3,4-dihydro-2H-naphthalen-1-ylidene)-5H-dibenzo[a,d]cycloheptene)

A two-necked, round-bottomed flask was installed to a reflux condensersystem. The compound 6 (290 mg, 0.5 mmol), diphenyl-p-tolyl-amine(227.94 mg, 1.5 mmol) and Na₂CO₃ (126 mg, 1.5 mmol) were added into theflask, and then the mixture was dissolved in a co-solvent systemcontaining ethylene glycol dimethyl ether (EGDME) and H₂O (5 mL,EGDME:H₂O=4:1), followed by adding Pd(PPh₃)₄ (17 mg, 3 mol %). After thereaction mixture was refluxed for 8 hours, the mixture was extracted bydichloromethane/H₂O (30 mL/30 mL) and the organic layer was collected.The collected organic layer was dried by adding magnesium sulfate,followed by being purified by column chromatography by using a mixtureof dichloromethane/n-hexane (1/1) as an eluent to obtain the compound 7c(229 mg, yield: 80%). The above reaction is represented by the chemicalequation (1-7c).

Spectral data as follow: M.W.: 911.14; m.p.: 466° C.; T_(g)=146° C.;T_(d)=547° C.; ¹H NMR (400 MHz, CDCl₃) δ 8.07 (d, J=8.5, 2H), 7.92-7.91(m, 2H), 7.82 (dd, J=8.5, 2.2, 4H), 7.47 (t, J=6.8, 1H), 7.40 (t, J=6.5,2H), 7.31-7.27 (m, 8H), 7.23-7.21 (m, 9H), 7.09-7.01 (m, 8H), 6.66 (d,J=7.4, 1H), 6.50 (d, J=7.8, 1H), 2.93-2.85 (m, 3H), 2.00-1.99 (m, 2H),1.86 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 150.64, 147.79, 147.19, 139.08,136.74, 131.76, 131.67, 131.04, 129.75, 129.43, 129.33, 129.22, 128.33,126.89, 124.83, 124.75, 124.52, 124.19, 123.05, 122.61, 41.38, 31.62,29.61, 29.09, 28.87, 24.01, 22.65, 14.15, 11.46; TLC R_(f)=0.65(CH₂Cl₂/hexanes, 1/1); High Resolution-MS calcd for C₆₇H₄₈N₄: 909.1248,found: 909.1249.

Example 8: Synthesis of Compound 14 (4-(naphthalen-2-yl)butanoic acid)

A two-necked flask was dried under vacuum, followed by being filled withnitrogen gas. The compound 13 (228 mg, 1 mmol), hydrazine (0.05 mL, 1mmol) and potassium hydroxide (190 mg, 1.3 mmol) were dissolved inbis(2-hydroxy-ethyl) ether (1.7 mL), followed by heating to 100° C. for100 minutes in an oil bath. Then, the flask was removed from the oilbath, followed by vacuum for 2-3 hours. The flask was then filled withnitrogen gas and heated to 230° C. for 5 hours. After the flask wascooled down, it was then placed in an ice bath. The reaction mixture wasthen washed by hydrochloric acid (15 mL, 6N) for several times to obtaina crude product. The crude product was then extracted by ether (100 mL)to collect the organic layer. The collected organic layer was dried byadding magnesium sulfate, followed by condensation by a rotaryevaporator. The resulting product was then recrystallized withcyclohexane to obtain the compound 14 (90 mg, yield: 42%). The abovereaction is represented by the chemical equation (2-1).

Spectral data as follow: M.W.: 214.26; ¹H NMR (400 MHz, CDCl₃) δ 7.79(t, J=8.5, 3H), 7.62 (s, 1H), 7.45-7.41 (m, 2H), 7.33 (d, J=8.2, 1H),2.84 (t, J=7.4, 2H), 2.41 (t, J=7.4, 2H), 2.06 (t, J=7.4, 2H); ¹³C NMR(100 MHz, CDCl₃) δ 179.29, 138.69, 137.33, 133.63, 132.15, 128.82,128.07, 127.63, 127.47, 127.20, 126.94, 126.65, 126.23, 125.99, 125.93,125.54, 125.51, 125.28, 123.71, 35.16, 33.57, 33.26, 32.21, 26.09,25.51.

Example 9: Synthesis of Compound 15 (2,3-dihydrophenanthren-4(1H)-one)

An addition funnel was installed on a tri-necked flask. The flask wasdried under vacuum, followed by being filled with nitrogen gas. Thecompound 14 (214 mg, 1 mmol) was dissolved in benzene (5 mL, dehydratedand purified in advance), followed by adding PCl₅ (270 mg, 1.3 mmol).After reacting at room temperature for 30 minutes, the flask was thenplaced in an ice bath. SnCl₄ (0.2 mL, 0.52 mg, 2 mmol) was addeddropwisely through the addition funnel into the flask at 0° C. (about 20minutes). After reacting for 1 hour at 0° C., the flask containing thereaction mixture was put in the ice bath. The reaction mixture wasextracted by EtOAc (30 mL) to collect the organic layer. The collectedorganic layer was dried by adding magnesium sulfate, and then purifiedby column chromatography with a mixture of EtOAc and hexanes (1/10) asan eluent to obtain compound 15 (92 mg, yield: 47%). The above reactionis represented by the chemical equation (2-2).

Spectral data as follow: M.W.: 196.24; ¹H NMR (400 MHz, CDCl₃) δ 9.40(d, J=8.7, 1H), 7.92 (d, J=8.3, 1H), 7.80 (d, J=8.0, 1H), 7.62 (t,J=7.4, 1H), 7.49 (t, J=7.4, 1H), 7.32 (d, J=8.4, 1H), 3.13 (t, J=6.0,2H), 2.79 (t, J=6.5, 2H), 2.23-2.17 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ200.46, 198.55, 146.75, 142.94, 135.75, 134.22, 132.83, 131.42, 130.05,128.84, 128.80, 128.29, 127.34, 126.98, 126.95, 126.71, 125.84, 124.84,122.79, 41.12, 38.40, 31.63, 25.65, 23.05, 22.79; TLC R_(f)=0.30(EtOAc/hexanes, 1/10).

Example 10a: Synthesis of Compound 16a(1-(2,3-dihydrophenanthren-4(1H)-ylidene)hydrazine)

A 100 mL, single-neck flask was placed on a Dean-Stark trap and thendried under vacuum. Ethanol (30 mL) was added to the flask, followed byadding the compound 15 (196 mg, 1 mmol) and hydrazine monohydrate (0.87mL, 18 mmol). The reaction mixture was refluxed for 6 hours at 120° C.,and then the flask was removed from the reflux system and cooled down toroom temperature. The ethanol was removed by the vacuum system and thenthe compound 16a (yield: 100%) was obtained. Because the product 16atended to decompose easily, it was used for the following reactionswithout purification. The above reaction is represented by the chemicalequation (2-3a).

Spectral data as follow: M.W.: 210.27; ¹H NMR (200 MHz, CDCl₃) δ 9.10(d, J=8.0, 1H), 7.82 (d, J=7.6, 1H), 7.72 (d, J=8.0, 1H), 7.48 (m, 2H),7.29 (d, J=2.4, 1H), 2.84 (t, J=5.8, 2H), 2.64 (t, J=6.8, 2H), 1.97 (q,J=6.0, 2H).

Example 11a: synthesis of compound 17a(Endo-(1,2,3,4,-tetratydro-1-phenanthrenyliden-2′-thirrane-3″-10,11-dihydro-5H-dibenzo[a,d]cycloheptene))

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 50 ml flask which was then dried under vacuum. The compound16a (210 mg, 1 mmol) dissolved in anhydrous dichloromethane (10 mL) wasthen transferred into the flask installed at bottom end of the Schlenktube by a double-tipped needle. At −30° C., dried silver(I) oxide (695mg, 3 mmol) and magnesium sulfate (1.24 g) were well mixed and thenpoured into the flask at bottom end of the Schlenk tube, followed bydropwisely addition of saturated potassium hydroxide solution (inmethanol, 2.35 mL) into the flask at bottom end of the Schlenk tube.After reacting for 40 minutes at −30° C., the Schlenk tube was invertedto filter out the solid impurities (i.e., silver oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at−30° C. The compound 2 (thioketone, 223 mg, 1 mmol) dissolved inanhydrous dichloromethane (10 mL, concentration: 0.1M) was slowlyinjected into the flask containing the filtrate with an air-tightsyringe until no bubbles were produced in the solution and the color ofthe solution became light green (the color of compound 2). Afterreacting for 9 hours at −30° C., the reaction mixture was added withsaturated, aqueous sodium bicarbonate solution (10 mL) to quench thereaction. The organic layer of the reaction mixture was then extractedwith dichloromethane (150 mL). Then, the collected organic layer wasdried by adding anhydrous magnesium sulfate, followed by filtration andcondensation to obtain a condensed solution. The condensed solution wasthen purified by column chromatography by using a mixture ofether/n-hexane (1/100) as an eluent, so as to obtain a crude product.The crude product was recrystallized with a mixture ofn-hexane/dichloromethane to obtain the compound 17a (235 mg, yield:58%). The above reaction is represented by the chemical equation (2-4a).

Spectral data as follow: M.W.: 402.55; m.p.: 164-167° C.; ¹H NMR: (400MHz, CDCl₃) δ 9.37 (d, J=8.7, 1H), 7.75-7.68 (m, 2), 7.35-7.15 (m, 5H),6.99-6.83 (m, 5H), 6.61 (t, J=7.0, 1H), 6.46 (d, J=7.3, 1H), 6.20 (d,J=11.7, 1H), 3.09-3.03 (m, 1H), 2.90-2.50 (m, 1H), 2.50-2.42 (m, 1H),1.87-1.76 (m, 1H), 1.46-1.41 (m, 2H); ¹³C NMR (100 MHz, CDCl₃) δ 139.55,138.55, 135.42 134.70, 134.60, 132.68, 131.80, 131.20, 130.87, 129.43,128.57, 128.28, 127.92, 127.68, 127.58, 127.35, 126.94, 126.84, 126.38,126.05, 126.01, 123.69, 123.47, 67.39, 58.36, 39.44, 31.10, 21.22; MS:(20 eV) 404 (9), 402 (M⁺, 100), 369 (95), 247 (10), 221 (10), 191 (43);Analysis: (C₂₉H₂₂S (402.55)) Calcd: C, 86.53; H, 5.51; Found: C, 86.47;H, 5.59; TLC: R_(f) 0.27 (hexane/ether, 100/1).

Example 12a: Synthesis of Compound 18a(5-(2,3-Dihydro-1H-phenanthren-4-ylidene)-5H-dibenzo[a,d]cycloheptene)

A stir bar was placed in a two-necked 50 mL flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 17a (402 mg, 1 mmol) was dissolved in anhydrous dimethylbenzene(20 mL) and followed by adding dried copper powder (635 mg, 10 mmol)into the flask. The flask was then put in an oil bath at 150° C. forreflux. The reaction mixture was refluxed for 2 hours, and then thered-brown copper powder became to black copper sulfide. After thereaction was completed, a crude product was collected with a filteringfunnel which was fitted inside with a filter paper. The flask was washedby anhydrous ether to collect the residual crude product in the flask.After filtration and condensation with a rotary evaporator, a whitesolid was obtained. The obtained solid was then recrystallized with amixture of n-hexane/dichloromethane to obtain the compound 18a (360 mg,yield: 98%). The above reaction is represented by the chemical equation(2-5a).

Spectral data as follow: M.W.: 370.48; ¹H NMR (400 MHz, CDCl₃) δ7.53-7.48 (m, 3H), 7.62-7.32 (m, 3H), 7.31-7.24 (m, 2H), 7.07-7.03 (m,4H), 6.94 (t, J=8.0, 1H), 6.70 (t, J=8.0, 1H), 6.50 (t, J=8.0, 1H), 6.30(d, J=8.0, 1H), 2.95-2.87 (m, 3H), 2.24-2.21 (m, 1H), 1.89-1.78 (m, 2H);NMR (100 MHz, CDCl₃) δ 141.24, 138.40, 138.11, 136.66, 136.46, 135.27,135.09, 134.33, 131.70, 131.69, 131.60, 128.44, 128.25, 128.12, 128.09,127.90, 127.24, 126.74, 126.49, 125.85, 125.75, 125.62, 124.39, 124.10,29.16, 27.13. 22.45; MS (20 eV) 370 (M⁺, 100), 192 (14); ElementalAnalysis. Calcd for C₂₉H₂₂: C, 94.01; H, 5.99; Found: C, 93.75; H, 6.33;TLC: R_(f)0.30 (hexane/ether, 100/1); UV λ_(max): 289 nm (ε 20937, inhexane).

Example 11b: Synthesis of Compound 17b(3″,4″-dihydro-2″H-dispiro[dibenzo[a,d][7]annulene-5,2′-thiirane-3′,1″-phenanthrene])

Each end (top and bottom) of a Schlenk tube was installed with atwo-necked 50 ml flask which was then dried under vacuum. The compound16b (237.1 mg, 1.12 mmol) dissolved in anhydrous dichloromethane (10 mL)was then transferred into the flask installed at bottom end of theSchlenk tube by a double-tipped needle. At −30° C., dried silver(I)oxide (389.7 mg, 1.7 mmol) and magnesium sulfate (0.73 g) were wellmixed and then poured into the flask at bottom end of the Schlenk tube,followed by dropwisely injected saturated potassium hydroxide solution(in methanol, 0.87 mL) into the flask at bottom end of the Schlenk tube.After reacting for 40 minutes at −30° C., the Schlenk tube was invertedto filter out the solid impurities (i.e., silver oxide and magnesiumsulfate) and thus to collect the dark-red filtrate in the othertwo-necked flask. Then the flask containing the filtrate was placed at0° C. The compound 2 (thioketone, 57.2 mg, 0.26 mmol) dissolved inanhydrous dichloromethane (4.6 mL, concentration: 0.1M) was slowlyinjected into the flask containing the filtrate with an air-tightsyringe until no bubbles were produced in the solution and the color ofthe solution became light green (the color of compound 2). Afterreacting for 10 hours at 0° C., the reaction mixture was added withsaturated, aqueous sodium bicarbonate solution (10 mL) to quench thereaction. The organic layer of the reaction mixture was then extractedwith ether (150 mL) for three times. Then, the collected organic layerwas dried by adding anhydrous magnesium sulfate, followed by filtrationand condensation to obtain a condensed solution. The condensed solutionwas then purified by column chromatography by using a mixture ofether/n-hexane (1/100) as an eluent, so as to obtain a crude product.The crude product was recrystallized with n-hexane to obtain thecompound 17b (54.8 mg, yield: 54%). The above reaction is represented bythe chemical equation (2-4b).

Spectral data as follow: m.p.: 224-225° C.; ¹H NMR: (400 MHz, CDCl₃)7.98 (d, J=7.5, 1H), 7.91 (d, J=8.5, 1H), 7.77 (d, J=7.8, 1H), 7.56 (d,J=7.8, 1H), 7.43-7.33 (m, 4H), 7.30-7.24 (m, 2H), 7.13 (t, J=7.3, 1H),6.95 (d, J=11.7, 1H), 6.95 (d, J=8.7, 1H), 6.62 (d, J=9, 1H), 6.45 (d,J=11.7, 1H), 3.20 (dt, J=16.8, 4, 1H), 3.08 (dt, J=16.8, 1H), 2.12-2.01(m, 2H), 1.78-1.76 (m, 1H), 1.48-1.43 (m, 1H); ¹³C NMR: (100 MHz, CDCl₃)138.83, 136.55, 134.74, 134.68, 133.99, 132.21, 131.50, 131.37, 130.58,130.48, 129.26, 128.38, 128.00, 128.00, 127.61, 126.95, 126.78, 126.49,126.42, 125.39, 125.22, 123.42, 123.16, 58.44, 35.26, 29.28, 26.00,22.02; MS: (20 eV) 404 (8), 402 (M⁺, 100), 369 (23), 191 (15); TLC:R_(f)0.53 (hexane/ether, 100/1).

Example 12b: Synthesis of Compound 18b(5-(3,4-dihydrophenanthren-1(2H)-ylidene)-5H-dibenzo[a,d][7]annulene)

A stir bar was placed in a two-necked 50 mL flask, and the flask wasthen equipped to a condenser, followed by being dried under vacuum. Thecompound 17b (55.5 mg, 0.13 mmol) was dissolved in anhydrousdimethylbenzene (10 mL) and followed by adding dried copper powder (88.2mg, 1.37 mmol) into the flask. The flask was then put in an oil bath at180° C. for reflux. The reaction mixture was refluxed for 2 hours, andthen the red-brown copper powder became to black copper sulfide. Afterthe reaction was completed, a crude product was collected with afiltering funnel which was fitted inside with a filter paper. The flaskwas washed by anhydrous ether to collect the residual crude product inthe flask. After filtration and condensation with a rotary evaporator, awhite solid was obtained. The obtained solid was then purified by columnchromatography by using n-hexane as an eluent and followed by beingrecrystallized with n-hexane to obtain the compound 18b (43.8 mg, yield:91%). The above reaction is represented by the chemical equation (2-5b).

Spectral data as follow: mp: 198-199° C.; M.W.: 370.49; ¹H NMR (400 MHz,CDCl₃) δ 7.92 (d, J=8.0, 1H), 7.57 (d, J=8.0, 1H), 7.41-6.95 (m, 12H),6.87 (d, J=8.0, 1H), 6.34 (d, J=8.0, 1H), 3.39-3.18 (m, 2H), 2.86 (d,J=12.0, 1H), 2.5-2.16 (m, 2H), 1.86 (t, J=12.0, 1H); ¹³C NMR (100 MHz,CDCl₃) δ 140.53, 138.89, 136.51, 134.40, 133.71, 133.56, 132.18, 132.17,131.88, 131.30, 131.04, 129.11, 128.38, 128.09, 128.04, 127.91, 127.76,127.46, 126.29, 126.15, 125.56, 125.22, 123.81, 123.23, 28.44, 26.30,24.87; MS (20 eV) 370 (M⁺, 100); Elemental Analysis. Calcd for C₂₉H₂₂:C, 94.01; H, 5.99; Found: C, 94.00; H, 5.98; TLC: R_(f)0.23 (hexane); UVλ_(max): 273 nm (ε 89580, in hexane).

Example 13: Synthesis of Compound 19(5-(2,3-dihydro-1H-phenanthren-4-ylidene)-5H-dibenzo[a,d]cycloheptene-10,11-dione)

A stir bar was placed in a two-necked, round-bottomed flask, and theflask was then installed to a reflux condenser system. The compound 18a(370 mg, 1 mmol) and benzeneseleninic anhydride (BSA, 720.26 mg, 2 mmol)were added into the flask and dissolved in chlorobenzene (10 mL),followed by refluxing for 5 hours until the color of the solution turnedto orange-red. The reaction mixture was filtered by a filtering funnel,which was fitted inside with silica gel (3 cm height) in advance. Thereaction mixture was filtered and washed with n-hexane first to removediphenyl diselenide, and all the crude products were then filtered withdichloromethane, followed by being purified by column chromatography byusing a mixture of EtOAc/hexane (1/30) as an eluent to obtain thecompound 19 (160 mg, yield: 40%). The above reaction is represented bythe chemical equation (2-6).

Spectral data as follow: M.W.: 400.46; ¹H NMR (400 MHz, CDCl₃) δ 8.20(d, J=8.4, 1H), 7.85-7.84 (m, 1H), 7.73-7.70 (m, 1H), 7.68-7.59 (m, 2H),7.50-7.46 (m, 2H), 7.33-7.28 (m, 3H), 7.25-7.14 (m, 3H), 6.95-6.93 (m,2H), 6.79 (t, J=5.8, 1H), 6.53 (t, J=6.0, 1H), 6.39 (d, J=7.6, 1H), 6.24(d, J=7.7, 1H), 3.07-3.03 (m, 2H), 2.94-2.87 (m, 1H), 2.28 (m, 1H),2.15-2.12 (m, 1H), 2.11-2.08 (m, 1H); ¹³C NMR (100 MHz, CDCl₃) δ 189.19,188.63, 143.13, 142.06, 139.46, 135.58, 135.47, 133.74, 132.83, 131.10,130.73, 129.11, 129.04, 128.60, 128.00, 127.93, 127.83, 127.70, 124.70,29.44, 29.20, 23.68; TLC R_(f)=0.33 (EtOAc/hexanes, 1/30).

Example 14: Synthesis of Compound 20(1,4-dibromo-quinoxaline-5-(2,3-dihydro-1H-phenanthren-4-ylidene)-5H-dibenzo[a,d]cycloheptene)

A two-necked, round-bottomed flask was installed to a reflux condensersystem. The compound 19 (400 mg, 1 mmol) and3,6-dibromobenzene-1,2-diamine (397 mg, 1.5 mmol) were dissolved bychloroform (10 mL), followed by addition of p-TSA (p-toluene sulfonicacid, 8.61 mg, 5 mol %). After the reaction mixture was refluxed for 8hours, it was extracted with a mixture of dichloromethane/H₂O (30 mL/30mL) to collect the organic layer. The collected organic layer was driedby adding magnesium sulfate, followed by being purified by columnchromatography by using a mixture of dichloromethane and hexanes (1/2)to obtain the compound 20 (472 mg, yield: 75%). The above reaction isrepresented by the chemical equation (2-7).

Spectral data as follow: M.W.: 630.37; ¹H NMR (200 MHz, CDCl₃) δ8.39-8.34 (m, 1H), 8.04-7.96 (m, 3H), 7.58-7.50 (m, 5H), 7.20-7.17 (m,1H), 7.16-7.12 (m, 4H), 6.79 (t, J=7.6, 1H), 6.44 (d, J=7.6, 1H),3.06-3.04 (m, 3H), 2.33-2.32 (m, 1H), 1.99-1.93 (m, 2H); ¹³C NMR (100MHz, CDCl₃) δ 135.24, 133.18, 132.06, 131.34, 130.21, 129.40, 128.28,127.79, 127.38, 127.11, 126.88, 125.79, 125.01, 124.63, 29.25, 27.77,22.45; TLC R_(f)=0.50 (CH₂Cl₂/Hexanes, 1/2).

Example 15: Synthesis of Compound 21(1,4-diphenyl-methoxyl-quinoxaline-5-(2,3-dihydro-1H-phenanthren-4-ylidene)-5H-dibenzo[a,d]cycloheptene)

A two-necked, round-bottomed flask was installed to a reflux condensersystem. The compound 20 (315 mg, 0.5 mmol), 4-methoxy-phenyl bonoic acid(227.94 mg, 1.5 mmol) and Na₂CO₃ (126 mg, 1.5 mmol) were added into theflask, and then the mixture was dissolved in ethylene glycol dimethylether/H₂O solution (5 mL, EGDME/H₂O=4:1), followed by adding Pd (PPh₃)₄(17 mg, 3 mol %). After the reaction mixture was refluxed for 8 hours,it was extracted with a mixture of dichloromethane/H₂O (30 mL/30 mL) tocollect the organic layer. The organic layer was dried by addingmagnesium sulfate, followed by being purified by column chromatographyby using a mixture of dichloromethane/hexanes (1/1) as an eluent toobtain the compound 21 (499 mg, yield: 73%). The above reaction isrepresented by the chemical equation (2-8).

Spectral data as follow: M.W.: 684.27; m.p.: 400° C.; T_(g)=137° C.; ¹HNMR (400 MHz, CDCl₃) δ 8.24 (d, J=7.3, 1H), 8.10 (d, J=8.6, 2H),8.02-7.94 (m, 3H), 7.81 (d, J=7.8, 1H), 7.56 (d, J=8.2, 1H), 7.51-7.49(m, 4H), 7.14-7.11 (m, 4H), 6.97-6.93 (m, 3H), 6.71 (t, J=7.6, 1H), 6.46(t, J=7.8, 1H), 6.39 (d, J=7.4, 1H), 3.96 (s, 3H), 3.93 (s, 3H),3.07-2.96 (m, 3H), 2.32 (m, 1H), 1.88-1.85 (m, 2H); NMR (100 MHz, CDCl₃)δ 159.30, 159.21, 150.97, 144.84, 143.34, 136.22, 132.09, 131.30,130.71, 129.73, 129.49, 129.30, 128.51, 128.16, 127.42, 127.13, 126.89,126.59, 125.79, 125.62, 124.84, 113.63, 113.33, 55.39, 29.69, 29.21,27.65, 22.36; TLC R_(f)=0.50 (CH₂Cl₂/hexanes, 1/1), High Resolution-MScalcd for C₄₉H₃₆N₂O₂: 684.2777, found: 684.2770.

In addition, the person having an ordinary skill in the art canunderstand that they can combine the reaction schemes shown above and/orsubstitute the starting materials in the above-listed examples tosynthesis a series of compounds with quinoxaline-fused dibenzosuberanebased helicenes which are represented by General Formula (1). Forexample, the compound 4a in chemical equation (1-5) can be replaced withany one of the compounds 4b to 4e synthesized in the Examples 4b to 4e,to synthesize the compounds which have the upper panel fragments similarto the compound 7a, 7b, or 7c but have the lower panel fragmentscorresponding to those in the compounds 4b to 4e, respectively accordingto the reaction schemes represented by the chemical equations (1-5) to(1-7a), (1-5) to (1-7b) or (1-5) to (1-7c). On the other hand, thecompound 18a in chemical equation (2-6) can be replaced by the compound18b, which is synthesized in the Example 12, to synthesize the compoundwhich has an upper panel fragment similar to the compound 21 but has anlower panel fragment corresponding to that in the compound 18b,according to the reaction schemes represented by the chemical equations(2-6) to (2-8).

Evaluation of the Series of the Quinoxaline-Fused Dibenzosuberane BasedHelicenes as Materials for the Organic Electroluminescent Device

The compounds of the chemical formulas (1) to (4), synthesized throughthe protocols provided as Example 1 to Example 7a, 7b, 7c, and Example 8to Example 15, respectively, were evaluated for their thermal,photophysical, and electrochemical properties, such as their wavelengthsof maximum absorption (Abs. λ_(max)), wavelengths of maximum emission(Em, λ_(max)), full width at half maximum (FWHM), quantum yield (Φ_(f)),oxidation potential (E_(ox)), reduction potential (E_(red)), the highestoccupied molecular orbital (E_(HOMO)), the lowest occupied molecularorbital (E_(LUMO)), energy gap (E_(g)), the melting temperature (T_(m)),the glass transition temperature (T_(g)) and the decompositiontemperature (T_(d)).

The wavelengths of maximum absorption (Abs. λ_(max)), the wavelengths ofmaximum emission (Em, λ_(max)), and full width at half maximum (FWHM)were measured in a solution using dichloromethane (for the compounds ofthe chemical formulas (1), (3) and (4)) or toluene (for the chemicalformula (2)) as the solvent. Quantum yield (Φ_(f)) was measured withHamamatsu C9920. The melting temperature and the glass transitiontemperature were measured by a differential scanning calorimeter (DSC).The decomposition temperatures were measured by a thermogravimetricanalyzer (TGA) and are considered to be the basis of the thermalstability for the device fabrication and optoelectronic performance.

The electrochemical properties, including E_(ox), E_(red), E_(HOMO),E_(LUMO), and E_(g), were measured by way of cyclic voltammetry (CV) ina solution using dichloromethane as a solvent. The energy levels of HOMO(E_(HOMO)), energy levels of LUMO (E_(LUMO)) and the relative energygaps of the compounds were determined by analyzing the correspondingUV-VIS absorption spectra. Platinum wire electrode was used as thecounter (auxiliary) electrode, carbon electrode was used as the workingelectrode and Ag was used as the reference electrode (which was immersedin hydrochloric acid in advance before use). Ferrocene was used as astandard. The redox potential of the ferrocene/ferrocenium (Fe/Fe+)redox couple was assumed at 0.51 V relative to vacuum. The CV curveswere calibrated using the Fe/Fe⁺ redox couple as an external standardwhich was measured under same condition before and after the measurementof samples. The energy level of Fe/Fe+ was assumed at −4.8 eV to vacuum.The energy gap (E_(g)) was the difference between the HOMO energy level(E_(HOMO)) and the energy level of LUMO (E_(LUMO)).

Those properties of the compounds of the chemical formula (1) tochemical formula (4) are shown in Table 1.

TABLE 1 chemical chemical chemical chemical compound formula (1) formula(2) formula (3) formula (4) Abs.λ_(max) (nm) 284, 369 322, 478 315, 450285, 364 Em, λ_(max) (nm) 500 652 586 498 FWHM (nm) 88 113 100 85 Φ_(f)(%) 58 24 64 64 E_(ox) (V) — 0.61, 0.82 1.00 — E_(red) (V) −1.60 −1.64−1.60 −1.66 E_(HOMO) (eV) −5.98 −5.28 −5.69 −5.92 E_(LUMO) (eV) −3.20−3.16 −3.20 −3.14 E_(g) (eV) 2.78 2.12 2.49 2.78 T_(m) (° C.) 289 292466 400 T_(g) (° C.) 127 108 146 137 T_(d) (° C.) 398 385 547 507

The absorption spectra of the compounds of the chemical formula (1) andchemical formula (4) were very similar because both of the compoundshave the same structures at the upper panel fragments. In addition, themaximal emission peaks of the compounds of chemical formula (1) andchemical formula (4) appeared around 500 nm and 498 nm, respectively.Thus, they emitted bluish green lights. The quinoxaline-fused fragmentsof the compounds of the chemical formula (1) and chemical formula (4)were excellent electron acceptors and high conjugation systems. Inaddition, at C₁ and C₄ positions, these quinoxaline-fused fragments wereconjugated with p-methoxyphenyl groups which are strong electron donors.Such configuration may donate the electrons to the core template of thequinoxaline-fused fragments. Thus, these two compounds have highfluorescent quantum yields.

The compounds of the chemical formula (2) and chemical formula (3) havearylamine substituents at C₁ and C₄ positions, whereas the compound ofthe chemical formula (2) has p-phenyl-diphenyl amino groups and chemicalformula (3) has N-methyl-phenyl-amino groups. Such configurations of thecompounds of the chemical formulas (2) and (3) may further increase theextent of conjugation of the quinoxaline-fused fragments when comparedwith the compounds of the chemical formulas (1) and (4). According toTable 1, the peaks of maximum absorption of the compounds of thechemical formula (2) and chemical formula (3) appeared around 450 nm and478 nm, respectively, which correspond to the intramolecular chargetransfer of the lone pair electrons from the nitrogen of the arylaminegroups to the core template of the quinoxaline-fused fragment (n-π*transitions). The peak of maximum emission of the compound of thechemical formula (2) appeared around 652 nm, with a full width at halfmaximum of 113 nm, which was in the range of pure red light (640 nm). Inaddition, the quantum yield of the compound of the chemical formula (2)was as high as 24%, which represented that the compound of the chemicalformula (2) was suitable as an excellent red electroluminescentmaterial. The peak of maximum emission of the compound of the chemicalformula (3) appeared around 586 nm, with a full width at half maximum of100 nm, and this compound emitted a yellow-orange light in the solution.In addition, the quantum yield of the compound of the chemical formula(3) was as high as 64%, which represents that the compound of thechemical formula (3) was suitable as an excellent yellow-orangeelectroluminescent material.

According to Table 1, the glass transition temperatures (T_(g)) of thesefour compounds ranged from 105° C. to 146° C. These compounds haveexcellent thermal stability as organic electroluminescent materials. Thecompound of chemical formula (3) with the highest molecular weight amongthese four compounds, has the highest melting temperature (466° C.) andglass transition temperature (146° C.). The decomposition temperaturesof the compounds of chemical formula (1) to chemical formula (4) wereall higher than 350° C., so that the decomposition caused by the heat isnot easily occurred during the thermal vacuum deposition process.Moreover, the decomposition temperatures of the compounds of chemicalformula (3) and chemical formula (4) were even higher (507° C. to 547°C.), which may be attributable to the higher molecular weight of thecompound of the chemical formula (3) and the greater sterically-hinderedstructure of its lower panel of the compound of the chemical formula(4), respectively. Based on the reasons mentioned above, these fourcompounds have excellent thermal stabilities, and are quite beneficialfor the organic electroluminescent device application.

The reduction potentials of the compounds of the chemical formula (1) tochemical formula (4) are occurred at their quinoxaline-fused fragmentsand are ranged from −1.60 V to −1.66 V. The compound of the chemicalformula (2) has two sets of reversible oxidation potentials, which isattributed to the two arylamine groups at its upper panel. The compoundof the chemical formula (3) has only one set of reversible oxidationpotential, which is attributed to the two sets of triarylamine groups atits upper panel. The reversible oxidation potential (1.00 V) of thecompound of the chemical formula (3) was highest among these fourcompounds, which is attributed to the good conjugation between its corequinoxaline-fused fragment and the two sets of triarylamine groups atboth sides. The oxidation or reduction profiles of the compounds of thechemical formula (1) to chemical formula (4) in CVs are all reversible,which are quite beneficial to the transport of electrons and holes.Therefore, these compounds are suitable for the organicelectroluminescent device with good stability and luminous efficiency.

The E_(HOMO) of the compounds of the chemical formula (1) and chemicalformula (4) are ranged from −5.98 eV to −5.28 eV. The E_(LOMO) of thecompounds of the chemical formula (1) and chemical formula (4) areranged from −3.20 eV to −3.12 eV. Comparing to the conventional metalcathode materials (i.e., LiF/Al) and ITO anode, the energy gaps betweenthe E_(LOMO) of the compounds of the chemical formula (1) and thechemical formula (4) to that of the metal cathode are about 0.50 eV to0.56 eV, and the energy gap between the E_(HOMO) of the compounds of thechemical formula (1) and chemical formula (4) to that of ITO anode areabout 1.22 eV to 1.28 eV. Moreover, the compounds of the chemicalformula (1) and chemical formula (4) have a core template with aquinoxaline-fused fragment and have the substituents which are mostlysimple aromatic ring derivatives. Hence, the compounds of the chemicalformula (1) and chemical formula (4) not only can be light-emittingmaterials but also theoretically have electron transport properties. Onthe other hand, the arylamine substituents of the compounds of thechemical formula (2) and chemical formula (3) have hole transportproperties, and their core quinoxaline-fused fragments have electrontransport properties, which will result in that the compounds of thechemical formula (2) and chemical formula (3) have ambipolar propertiesand are suitable not only to be materials for the layer with bothelectron transport and light-emitting properties but also to bematerials for the layer with both hole transport and light-emittingproperties of the organic electroluminescent device.

The Device Efficiency for Compounds (Chemical Formula (1) to ChemicalFormula (4)) which were Used in the Organic Electroluminescent Devices

Configurations of the Organic Electroluminescent Devices

The unit structure of the present Example is ITO/hole transport layer(40 nm)/materials for testing (40 nm)/hole blocking layer (10nm)/electron transport layer (40 nm)/electron injection layer (1 nm)/Al.In the units 2, 5, 9, and 10, the to-be-tested materials of the chemicalformula (1) to chemical formula (4) are used for the layer with bothelectron transport and light-emitting properties. In the units 7 and 8,the to-be-tested materials of the chemical formula (2) and chemicalformula (3) are used for the layer with both hole transport andlight-emitting properties. In the units 4, 6 and 11, the to-be-testedmaterials of the chemical formula (1), chemical formula (3) and chemicalformula (4) are used for the light-emitting layer. The material of firstelectrode layer is ITO. The material of second electrode layer isaluminum with the thickness of 100 nm. The material of the holetransport layer isN,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB)with the thickness of 40 nm. The material of hole blocking layer is2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) with the thicknessof 10 nm. The material of the electron transport layer istris-(8-hydroxyquinoline) aluminum (Alq₃) with the thickness of 40 nm.The material of the electron injection layer is LiF with the thicknessof 1 nm.

Efficiency Evaluation of the Organic Luminescent Units Fabricated asAbove

The organic luminescent units fabricated as above were evaluated fortheir wavelengths of maximum emission (Em, λ_(max)), turn-on voltages(V_(on)), working voltages (V_(@20 mA/cm) ²) at 20 mA/cm², currentefficiencies η_(c) (cd/A), power efficiencies η_(p) (lm/W), externalquantum efficiencies η_(ext) (EQE, %), and luminance (L, cd/m²). Thedevice configurations of each OLED unit are shown in Table 2 and thecharacteristics of these OLED units are shown in Table 3.

TABLE 2 Second Electron Electron Hole To-be- Hole First elec- injec-trans- block- tested trans- elec- Unit trode tion port ing material porttrode 1 Al LiF Alq₃ — — NPB ITO 2 Al LiF — — Chemical NPB ITO formula(1) 3 Al LiF Alq₃ BCP — NPB ITO 4 Al LiF Alq₃ BCP Chemical NPB ITOformula (1) 5 Al LiF — — Chemical NPB ITO formula (4) 6 Al LiF Alq₃ BCPChemical NPB ITO formula (4) 7 Al LiF Alq₃ BCP Chemical — ITO formula(2) 8 Al LiF Alq₃ BCP Chemical — ITO formula (3) 9 Al LiF — — ChemicalNPB ITO formula (2) 10 Al LiF — — Chemical NPB ITO formula (3) 11 Al LiFAlq₃ BCP Chemical NPB ITO formula (3)

TABLE 3 Unit 1 2 3 4 5 6 7 8 9 10 11 Em, λ_(max) 522 514 514 516 544 544650 578 656 584 588 fwhm 112 112 100 98 114 112 128 118 124 116 114V_(on) (V) 4.7 4.2 4.2 6 4.4 6.2 4.5 5.1 4.8 2.8 5 V_(@20 mA/cm) ² 6.67.6 7.6 10.4 11.1 11.3 7.53 7.72 8.14 7.21 8.04 η_(ext) (%) 1.36 0.410.41 2.3 0.32 1 0.24 0.20 0.4 0.34 1.42 η_(c) (cd/A) 4.2 1.3 1.3 7.2 1.13.2 0.2 0.3 0.3 1.0 3.8 η_(p) (lm/W) 2 0.6 0.6 2.2 0.3 0.9 0.1 0.1 0.10.4 1.4 L 838 262 262 1427 217 631 30 57 48 172 690

Regarding to the units 1 to 4, the to-be-tested materials were thecompound of the chemical formula (1) and emitted green fluorescents. Inthe unit 2, the compound of the chemical formula (1) was used as thematerial of the layer having both electron transport and light-emittingproperties, and at 20 mA/cm² its η_(ext) was 0.4%, η_(c) was 1.3 cd/A,η_(p) was 0.6 lm/W and luminance was 262 cd/m². On the other hand, inthe unit 4, the compound of the chemical formula (1) was used as thematerial of the light-emitting layer, and at 20 mA/cm² its η_(ext) was2.3%, η_(c) was 7.2 cd/A, η_(p) was 2.2 lm/W, and luminance was 1427cd/m². Accordingly, the units 2 and 4 are both suitable to be greenorganic luminescent units, and, in general, the unit 4 may have a betterperformance than the unit 2. Regarding to the units 5 to 6, theto-be-tested materials were the compound of the chemical formula (4) andemitted yellow-green fluorescents. In the unit 5, the compound of thechemical formula (4) was used as the material of the layer having bothelectron transport and light-emitting properties, and at 20 mA/cm² itsη_(ext) was 0.3%, η_(c) was 1.1 cd/A, η_(p) was 0.3 lm/W and luminancewas 217 cd/m². On the other hand, in the unit 6, the compound of thechemical formula (4) was as the material of the light-emitting layer,and at 20 mA/cm² its η_(ext) was 1.0%, η_(c) was 3.2 cd/A, η_(p) was 0.9lm/W, and luminance was 630 cd/m². Accordingly, the units 5 and 6 aresuitable to be yellow-green organic luminescent units, and, in general,the unit 6 may have a better performance than the unit 5. Therefore, inthe present Example, the units which have the helicenes of the chemicalformula (1) and chemical formula (4) functioned as pure light-emittinglayer had better performance in general.

As mentioned above, the compounds of the chemical formula (2) andchemical formula (3) have ambipolar properties including hole transportand electron transport. Thus, in the units 7 and 8 in the presentExample, the compounds of the chemical formula (2) (for unit 7) andchemical formula (3) (for unit 8) were used as the materials of thelayer having both hole transport and light-emitting properties.According to Table 3, the BCP hole blocking layer effectively restrainedthe holes to stay in the light-emitting layer. The CIE_(xy) coordinatesof the unit 7 was (0.65, 0.34), which represented it emitted a saturatedred light. At 20 mA/cm², the unit 7 had an η_(ext) of 0.3%, η_(c) of 0.2cd/A, and η_(p) of 0.1 lm/W. Meanwhile, the unit 8 emitted an orangelight, and, at 20 mA/cm², it had an η_(ext) of 0.2%, η_(c) of 0.2 cd/A,and η_(p) of 0.1 lm/W. In addition, the energy gaps between the E_(HOMO)of the compounds of the chemical formula (2) and the chemical formula(3) and that of Alq₃ are 0.72 eV (chemical formula (2)) and 0.31 eV(chemical formula (3)), respectively, some holes in the units were foundto still enter Alq₃ without the BCP hole blocking layer. Such phenomenamight be attributable to that the upper panel of the compounds of thechemical formula (2) and chemical formula (3) which have two para-linkedarylamine substituents to the aromatic ring of the fused quinoxalinefragment, which is similar to the configuration of the hole transportmaterial NPB. Therefore, such configurations of the compounds of thechemical formula (2) and chemical formula (3) may help the holes to betransported to the Alq₃ electron transport layer much easier.

The efficacies of the units 9 and 10 were evaluated, and the compoundsof the chemical formula (2) and chemical formula (3) were used as thematerials of the layer having both electron transport and light-emittingproperties, and NPB was used as the material of the hole transportlayer. The CIE_(Xy) coordinates of the unit 9 was (0.66, 0.33), whichrepresented it emitted an ordinary saturated red luminescence. At 20mA/cm², the unit 9 had an η_(ext) of 0.4%, η_(c) of 0.3 cd/A, and η_(p)of 0.1 lm/W. Meanwhile, the unit 10 emitted an orange luminescence, and,at 20 mA/cm², it had an η_(ext) of 0.34%, η_(c) of 1.0 cd/A, and η_(p)of 0.4 lm/W.

In addition, in the unit 11, the compound of the chemical formula (3)was used as the material of the light-emitting layer. The unit 11 wasfound to emit an orange luminescence, and, at 20 mA/cm², the unit 11 hadan η_(ext) of 1.42%, η_(c) of 3.8 cd/A, and η_(p) of 1.4 lm/W.Accordingly, the unit 11 was suitable for an organic luminescent unitswhich emitted an orange luminescence.

In summary, a series of materials for organic electroluminescent devicewhich emitted green/yellow-green/orange/yellow-orange/red luminescenceare provided according to the present disclosure. The quinoxaline-fuseddibenzosuberane based helicenes according to the embodiments of thepresent invention have excellent fluorescence quantum effects andthermal stabilities. Therefore, the quinoxaline-fused dibenzosuberanebased helicenes are suitable for organic electroluminescent devices.Meanwhile, suitable configurations of units can also be found in theembodiments, which have good stabilities and luminous efficiencies.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitingsense. Various modifications of the disclosed embodiments, as well asalternative embodiments, will be apparent to persons skilled in the art.It is, therefore, contemplated that the appended claims will cover allmodifications that fall within the true scope of the invention.

What is claimed is:
 1. A quinoxaline-fused dibenzosuberane basedhelicene, comprising a structure of the following General Formula (1),

wherein A is represented by General Formula (2), General Formula (3a) orGeneral Formula (3b);

wherein X is an oxygen atom, sulfur atom, amino group, or —(CH₂)_(n), nis 0, 1, or 2; R₁ and R₂ are both independently a hydrogen atom, ahalogen atom, General Formula (4), General Formula (5) or GeneralFormula (6); and

wherein R₃ to R₁₅ are independently selected from the group consistingof a hydrogen atom, a halogen atom, a cyano group, an alkyl group, acycloalkyl group, an alkoxy group, a haloalkyl group, a thioalkyl group,a silyl group, an alkenyl group, an aryl group, and an amino group. 2.The quinoxaline-fused dibenzosuberane based helicene of claim 1, whereinthe alkyl group is selected from the group consisting of a substitutedor unsubstituted straight-chain alkyl group with the carbon number of 1to 6, and a substituted or unsubstituted branched-chain alkyl group withthe carbon number of 3 to 6, the cycloalkyl group is a substituted orunsubstituted cycloalkyl group with the carbon number of 3 to 6, thealkoxy group is selected from the group consisting of a substituted orunsubstituted straight-chain alkoxy group with the carbon number of 1 to6, and a substituted or unsubstituted branched-chain alkoxy group withthe carbon number of 3 to 6, the haloalkyl group is selected from thegroup consisting of a substituted or unsubstituted straight-chainhaloalkyl group with the carbon number of 1 to 6, and a substituted orunsubstituted branched-chain haloalkyl group with the carbon number of 3to 6, the thioalkyl group is selected from the group consisting of asubstituted or unsubstituted straight-chain thioalkyl group with thecarbon number of 1 to 6, and a substituted or unsubstitutedbranched-chain thioalkyl group with the carbon number of 3 to 6, thesilyl group is selected from the group consisting of a substituted orunsubstituted straight-chain silyl group with the carbon number of 1 to6, and a substituted or unsubstituted branched-chain silyl group withthe carbon number of 3 to 6, the alkenyl group is selected from thegroup consisting of a substituted or unsubstituted straight-chainalkenyl group with the carbon number of 2 to 6, and a substituted orunsubstituted branched-chain alkenyl group with the carbon number of 3to 6, the aryl group is a substituted or unsubstituted aromatichydrocarbon with the carbon number of 6 to 16, or a substituted orunsubstituted hetero aromatic ring with the carbon number of 5 to 16,and the amino group is a secondary amino group or a tertiary aminogroup.
 3. The quinoxaline-fused dibenzosuberane based helicene of claim1, wherein R₁₃ is an amino group or a substituted or unsubstitutedstraight-chain alkyl group with the carbon number of 1 to
 6. 4. Thequinoxaline-fused dibenzosuberane based helicene of claim 1, wherein R₁₄is a substituted or unsubstituted straight-chain alkyl group with thecarbon number of 1 to
 6. 5. The quinoxaline-fused dibenzosuberane basedhelicene of claim 1, wherein R₁₅ is an aryl group or a substituted orunsubstituted straight-chain alkyl group with the carbon number of 1 to6.
 6. The quinoxaline-fused dibenzosuberane based helicene of claim 1,being represented by one of following chemical formula I to chemicalformula IV.


7. The quinoxaline-fused dibenzosuberane based helicene of claim 1,having glass transition temperatures ranged from 108° C. to 146° C. anddecomposition temperatures ranged from 385° C. to 547° C.
 8. Thequinoxaline-fused dibenzosuberane based helicene of claim 1, havingoxidation potentials ranged from 0.6V to 1.0V and redox potentialsranged from −1.60V to −1.66V.
 9. The quinoxaline-fused dibenzosuberanebased helicene of claim 1, having highest occupied molecular orbitalenergy levels (E_(HOMO)) ranged from −5.28 eV to −5.98 eV and lowestunoccupied molecular orbital energy levels (E_(LUMO)) ranged from −3.14eV to −3.20 eV.
 10. The quinoxaline-fused dibenzosuberane based heliceneof claim 6, which is applied in an organic electroluminescent device forbeing as a light emitting material, a hole-transporting material and/oran electron-transporting material.